diff --git a/.github/workflows/build-and-tests.yaml b/.github/workflows/build-and-tests.yaml
new file mode 100644
index 0000000..dc47c59
--- /dev/null
+++ b/.github/workflows/build-and-tests.yaml
@@ -0,0 +1,19 @@
+name: Build & Test
+run-name: ""
+on:
+  push:
+  pull_request:
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  Build-and-Test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repository code
+        uses: actions/checkout@v4
+      - name: Build the workspace
+        run: cargo build --verbose
+      - name: Test the workspace
+        run: cargo test --verbose
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ea8c4bf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
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diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000..e8a5904
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,242 @@
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diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..779e860
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,6 @@
+[workspace]
+resolver = "2"
+members = [
+    "net_income_germany",
+    "net_income_germany_cmd",
+]
\ No newline at end of file
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..e8e183a
--- /dev/null
+++ b/README.md
@@ -0,0 +1,4 @@
+# Net Income (Germany)
+[![Build & Test](https://github.com/awinterstein/net-income-germany/actions/workflows/build-and-tests.yaml/badge.svg)](https://github.com/awinterstein/net-income-germany/actions/workflows/build-and-tests.yaml)
+
+See documentation for the net income module in the sudirectory [net_income_germany](net_income_germany/).
diff --git a/net_income_germany/Cargo.lock b/net_income_germany/Cargo.lock
new file mode 100644
index 0000000..5c6a21f
--- /dev/null
+++ b/net_income_germany/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "net-income-germany"
+version = "0.1.0"
diff --git a/net_income_germany/Cargo.toml b/net_income_germany/Cargo.toml
new file mode 100644
index 0000000..dd86950
--- /dev/null
+++ b/net_income_germany/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "net-income-germany"
+description = "Net income calculation for a given gross income based on the German social security and income tax rules."
+publish = ["cerritus"]
+license = "MPL-2.0"
+version = "0.1.0"
+edition = "2021"
+authors = ["Adrian Winterstein <adrian@winterstein.biz>"]
+repository = "https://deposito.cerritus.eu/freelancing/net-income-germany"
diff --git a/net_income_germany/README.md b/net_income_germany/README.md
new file mode 100644
index 0000000..0fa754e
--- /dev/null
+++ b/net_income_germany/README.md
@@ -0,0 +1,27 @@
+# net-income-germany
+
+Calculates the net income from a given yearly gross income.
+
+## Example
+```rust
+// set the necessary input data values
+let tax_data = net_income_germany::TaxData {
+    gross_income: 80000, // the gross income of one year
+    expenses: 5300, // the tax-deductible expenses of one year
+    fixed_retirement: Some(800), // an optional fixed monthly retirement rate (otherwise percentage applies)
+    self_employed: false, // whether social security taxes should be calculated for a self-employed person
+    married: false, // whether tax splitting due to marriage should apply
+};
+
+// create the default configuration for a specific year
+let config = net_income_germany::config::create(2025)?;
+
+// do the tax calculation based on the input data values
+let tax_result = net_income_germany::calculate(&config, &tax_data)?;
+
+// access the results (in this example just the resulting net income)
+println!("Net income: {}", tax_result.net_income);
+
+```
+
+License: MPL-2.0
diff --git a/net_income_germany/src/config.rs b/net_income_germany/src/config.rs
new file mode 100644
index 0000000..03c83f4
--- /dev/null
+++ b/net_income_germany/src/config.rs
@@ -0,0 +1,190 @@
+//! Tax and social security configurations (e.g, the rates to apply on the income) per year.
+//!
+//! There are configurations available based on the German laws for the years 2024 and 2025.
+
+// values for the social security (health and retirement) can be found on the website of the health ministry:
+// https://www.bundesgesundheitsministerium.de/beitraege
+
+/// Configuration for the state-operated health insurance used as part of the social security calculations.
+#[derive(Debug)]
+pub struct HealthInsuranceConfig {
+    pub premium_general: f32,
+    pub premium_general_reduced: f32,
+    pub premium_additional: f32,
+    pub premium_nursing: f32,
+    pub premium_nursing_additional: f32,
+    pub min_income: f32, // minimum income that is used for the health insurance calculation (only self-employed)
+    pub max_income: f32, // maximum income that is used for the health insurance calculation
+}
+
+/// Configuration for the state-operated retirement insurance used as part of the social security calculations.
+#[derive(Debug)]
+pub struct RetirementInsuranceConfig {
+    pub premium: f32,
+    pub max_income: f32,
+}
+
+#[derive(Debug)]
+pub struct UnemploymentInsuranceConfig {
+    pub premium: f32,
+    pub max_income: f32,
+}
+
+#[derive(Debug, Clone)]
+pub struct TaxRange {
+    pub lower_limit: u32,
+    pub upper_limit: u32,
+    pub rate_min: f32,
+    pub rate_max: f32,
+}
+
+#[derive(Debug)]
+pub struct SolidaryAdditionConfig {
+    pub exemption_level: u32,
+    pub rate: f32,
+    pub max_percentage: f32,
+}
+
+#[derive(Debug)]
+pub struct IncomeTaxConfig {
+    pub tax_ranges: Vec<TaxRange>,
+    pub solidary_addition_config: SolidaryAdditionConfig,
+}
+
+/// Main configuration struct that contains all the needed tax and social security configurations.
+#[derive(Debug)]
+pub struct Config {
+    pub health_insurance: HealthInsuranceConfig,
+    pub retirement_insurance: RetirementInsuranceConfig,
+    pub unemployment_insurance: UnemploymentInsuranceConfig,
+    pub income_tax: IncomeTaxConfig,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        return create(2025).unwrap();
+    }
+}
+
+/// Creates the configuration for the given year.
+pub fn create(year: u32) -> Result<Config, &'static str> {
+    match year {
+        2025 => Ok(Config {
+            retirement_insurance: RetirementInsuranceConfig {
+                premium: 0.186,
+                max_income: 8050.0,
+            },
+            health_insurance: HealthInsuranceConfig {
+                premium_general: 0.146,
+                premium_general_reduced: 0.14,
+                premium_additional: 0.0245,
+                premium_nursing: 0.036,
+                premium_nursing_additional: 0.006,
+                min_income: 1248.32,
+                max_income: 5512.5,
+            },
+            unemployment_insurance: UnemploymentInsuranceConfig {
+                premium: 0.026,
+                max_income: 8050.0,
+            },
+            income_tax: IncomeTaxConfig {
+                tax_ranges: vec![
+                    TaxRange {
+                        lower_limit: 0,
+                        upper_limit: 12096,
+                        rate_min: 0.00,
+                        rate_max: 0.00,
+                    },
+                    TaxRange {
+                        lower_limit: 12097,
+                        upper_limit: 17444,
+                        rate_min: 0.14,
+                        rate_max: 0.2397,
+                    },
+                    TaxRange {
+                        lower_limit: 17445,
+                        upper_limit: 68481,
+                        rate_min: 0.2397,
+                        rate_max: 0.42,
+                    },
+                    TaxRange {
+                        lower_limit: 68481,
+                        upper_limit: 277826,
+                        rate_min: 0.42,
+                        rate_max: 0.42,
+                    },
+                    TaxRange {
+                        lower_limit: 277826,
+                        upper_limit: u32::MAX,
+                        rate_min: 0.45,
+                        rate_max: 0.45,
+                    },
+                ],
+                solidary_addition_config: SolidaryAdditionConfig {
+                    exemption_level: 19950,
+                    rate: 0.055,
+                    max_percentage: 0.119,
+                },
+            },
+        }),
+        2024 => Ok(Config {
+            retirement_insurance: RetirementInsuranceConfig {
+                premium: 0.186,
+                max_income: 7550.0,
+            },
+            health_insurance: HealthInsuranceConfig {
+                premium_general: 0.146,
+                premium_general_reduced: 0.14,
+                premium_additional: 0.012,
+                premium_nursing: 0.034,
+                premium_nursing_additional: 0.006,
+                min_income: 1178.33,
+                max_income: 5175.0,
+            },
+            unemployment_insurance: UnemploymentInsuranceConfig {
+                premium: 0.026,
+                max_income: 7550.0,
+            },
+            income_tax: IncomeTaxConfig {
+                tax_ranges: vec![
+                    TaxRange {
+                        lower_limit: 0,
+                        upper_limit: 11784,
+                        rate_min: 0.00,
+                        rate_max: 0.00,
+                    },
+                    TaxRange {
+                        lower_limit: 11784,
+                        upper_limit: 17005,
+                        rate_min: 0.14,
+                        rate_max: 0.2397,
+                    },
+                    TaxRange {
+                        lower_limit: 17005,
+                        upper_limit: 66760,
+                        rate_min: 0.2397,
+                        rate_max: 0.42,
+                    },
+                    TaxRange {
+                        lower_limit: 66760,
+                        upper_limit: 277825,
+                        rate_min: 0.42,
+                        rate_max: 0.42,
+                    },
+                    TaxRange {
+                        lower_limit: 277825,
+                        upper_limit: u32::MAX,
+                        rate_min: 0.45,
+                        rate_max: 0.45,
+                    },
+                ],
+                solidary_addition_config: SolidaryAdditionConfig {
+                    exemption_level: 18130,
+                    rate: 0.055,
+                    max_percentage: 0.119,
+                },
+            },
+        }),
+        _ => Err("No configuration available for given year."),
+    }
+}
diff --git a/net_income_germany/src/income_tax.rs b/net_income_germany/src/income_tax.rs
new file mode 100644
index 0000000..960af33
--- /dev/null
+++ b/net_income_germany/src/income_tax.rs
@@ -0,0 +1,141 @@
+use crate::config::{IncomeTaxConfig, SolidaryAdditionConfig, TaxRange};
+
+impl TaxRange {
+    /// Calculate the range from the upper and lower limit.
+    pub fn range(&self) -> u32 {
+        self.upper_limit - self.lower_limit
+    }
+}
+
+pub fn calculate(config: &IncomeTaxConfig, taxable_income: u32, together: bool) -> u32 {
+    let tax = calculate_income_tax(&config, taxable_income, together);
+    let tax_solidarity =
+        calculate_solidarity_addition(tax, together, &config.solidary_addition_config);
+
+    return tax + tax_solidarity;
+}
+
+fn deduct_tax_for_one_range(income: u32, tax_range: &TaxRange) -> f32 {
+    // income so small, that this tax range does not apply
+    if income <= tax_range.lower_limit {
+        return 0.0;
+    }
+
+    // remove the lower limit from the income (as everything below is taxed in lower ranges)
+    // and make sure that not more than the current tax range of the income is considered
+    let taxed_income = (income - tax_range.lower_limit).min(tax_range.range());
+
+    let income_range = tax_range.range() as f32;
+    let taxed_income = taxed_income as f32;
+
+    let rate_diff = tax_range.rate_max - tax_range.rate_min;
+    let effective_rate_diff = taxed_income / income_range * rate_diff;
+
+    let effective_rate = tax_range.rate_min + effective_rate_diff / 2.0;
+
+    return taxed_income * effective_rate;
+}
+
+fn calculate_income_tax(config: &IncomeTaxConfig, income: u32, together: bool) -> u32 {
+    let mut tax_sum = 0.0;
+
+    // for married couples the taxes are calculated based on half of the combined income
+    let income = if together { income / 2 } else { income };
+
+    for tax_range in &config.tax_ranges {
+        let tax = deduct_tax_for_one_range(income, tax_range);
+
+        tax_sum = tax_sum + tax;
+    }
+
+    if together {
+        // the tax value needs to be doubled again after calculating with half for married couples
+        return tax_sum as u32 * 2;
+    } else {
+        return tax_sum as u32;
+    }
+}
+
+fn calculate_solidarity_addition(
+    tax: u32,
+    together: bool,
+    solidarity_addition_config: &SolidaryAdditionConfig,
+) -> u32 {
+    let tax_exemption_level = if together {
+        solidarity_addition_config.exemption_level * 2
+    } else {
+        solidarity_addition_config.exemption_level
+    };
+
+    if tax < tax_exemption_level {
+        return 0;
+    }
+
+    let max_solidarity_addition =
+        (tax - tax_exemption_level) as f32 * solidarity_addition_config.max_percentage;
+    let solidarity_addition = tax as f32 * solidarity_addition_config.rate;
+
+    return solidarity_addition.min(max_solidarity_addition) as u32;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::config::create as create_config;
+
+    struct Data {
+        i: u32,
+        o: u32,
+    }
+
+    #[test]
+    fn test_tax_calculation_2024() {
+        // the test data is based on the income tax calculator of the
+        // German ministry of finances (https://www.bmf-steuerrechner.de)
+        let test_data = vec![
+            Data { i: 11791, o: 0 },
+            Data { i: 11792, o: 1 },
+            Data { i: 17008, o: 991 },
+            Data { i: 18000, o: 1231 },
+            Data { i: 46231, o: 9544 },
+            Data { i: 66760, o: 17402 },
+            Data {
+                i: 277825,
+                o: 111882,
+            },
+        ];
+
+        test_tax_calculation(&test_data, 2024, false);
+    }
+
+    #[test]
+    fn test_tax_calculation_married_2024() {
+        // the test data is based on the income tax calculator of the
+        // German ministry of finances (https://www.bmf-steuerrechner.de)
+        let test_data = vec![
+            Data { i: 23583, o: 0 },
+            Data { i: 23584, o: 2 },
+            Data { i: 50000, o: 6046 },
+            Data { i: 66760, o: 10804 },
+            Data {
+                i: 277825,
+                o: 100659,
+            },
+            Data {
+                i: 555650,
+                o: 223765,
+            },
+        ];
+
+        test_tax_calculation(&test_data, 2024, true);
+    }
+
+    fn test_tax_calculation(test_data: &Vec<Data>, year: u32, together: bool) {
+        let config = create_config(year).unwrap();
+
+        for data in test_data {
+            let result = calculate(&config.income_tax, data.i, together);
+            assert_eq!(result, data.o);
+        }
+    }
+}
diff --git a/net_income_germany/src/lib.rs b/net_income_germany/src/lib.rs
new file mode 100644
index 0000000..8607663
--- /dev/null
+++ b/net_income_germany/src/lib.rs
@@ -0,0 +1,100 @@
+//! Calculates the net income from a given yearly gross income.
+//!
+//! # Example
+//! ```
+//! # fn main() -> Result<(), &'static str> {
+//! // set the necessary input data values
+//! let tax_data = net_income_germany::TaxData {
+//!     gross_income: 80000, // the gross income of one year
+//!     expenses: 5300, // the tax-deductible expenses of one year
+//!     fixed_retirement: Some(800), // an optional fixed monthly retirement rate (otherwise percentage applies)
+//!     self_employed: false, // whether social security taxes should be calculated for a self-employed person
+//!     married: false, // whether tax splitting due to marriage should apply
+//! };
+//!
+//! // create the default configuration for a specific year
+//! let config = net_income_germany::config::create(2025)?;
+//!
+//! // do the tax calculation based on the input data values
+//! let tax_result = net_income_germany::calculate(&config, &tax_data)?;
+//!
+//! // access the results (in this example just the resulting net income)
+//! println!("Net income: {}", tax_result.net_income);
+//!
+//! # Ok(())
+//! # }
+//! ```
+
+pub mod config;
+mod income_tax;
+mod social_security;
+
+/// Input data struct for the tax calculation.
+pub struct TaxData {
+    /// The gross income of one year.
+    pub gross_income: u32,
+
+    /// The expenses of one year that will be deducted from the gross income, before calculating the income taxes.
+    pub expenses: u32,
+
+    /// Optional value of a fixed monthly retirement insurance rate. If this is set, then this rate is used for every
+    /// month. Otherwise, the retirement insurance rate is calculated by a percentage of the income.
+    pub fixed_retirement: Option<u32>,
+
+    /// Whether the calculations should be done for a self-employed person.
+    pub self_employed: bool,
+
+    /// Whether the income should be split for two people according to tax law.
+    pub married: bool,
+}
+
+/// Result struct of the tax calculation.
+pub struct TaxResult {
+    /// The net income after deducting social security taxes and income taxes.
+    pub net_income: i32,
+
+    /// The social security taxes that were deducted from the gross income.
+    pub social_security_taxes: u32,
+
+    /// The income taxes that were deducted from the gross income.
+    pub income_taxes: u32,
+}
+
+impl TaxResult {
+    /// Returns how much of the gross income was spent on social security and income taxes.
+    pub fn get_tax_ratio(&self) -> f32 {
+        let taxes = (self.social_security_taxes + self.income_taxes) as f32;
+        return taxes / (self.net_income as f32 + taxes);
+    }
+}
+
+/// Calculates social security taxes and income taxes based on the given income.
+///
+/// Returns the remaining net income and the calculated social security taxes and income taxes.
+pub fn calculate(config: &config::Config, tax_data: &TaxData) -> Result<TaxResult, &'static str> {
+    // calculate the social security taxes
+    let social_security = social_security::calculate(
+        &config.health_insurance,
+        &config.retirement_insurance,
+        &config.unemployment_insurance,
+        &tax_data,
+    )?;
+
+    // reduce income by social security taxes and calculate income taxes on this
+    let taxable_income =
+        tax_data.gross_income as i32 - social_security as i32 - tax_data.expenses as i32;
+    let taxes = income_tax::calculate(
+        &config.income_tax,
+        taxable_income.max(0) as u32,
+        tax_data.married,
+    );
+
+    // store the results in the result struct
+    let tax_result = TaxResult {
+        net_income: taxable_income - taxes as i32,
+        social_security_taxes: social_security as u32,
+        income_taxes: taxes,
+    };
+
+    return Ok(tax_result);
+}
diff --git a/net_income_germany/src/social_security.rs b/net_income_germany/src/social_security.rs
new file mode 100644
index 0000000..1039df0
--- /dev/null
+++ b/net_income_germany/src/social_security.rs
@@ -0,0 +1,163 @@
+use crate::config::{
+    HealthInsuranceConfig, RetirementInsuranceConfig, UnemploymentInsuranceConfig,
+};
+use crate::TaxData;
+
+/// Calculate the social security payment from the given health and retirement insurance configuration and the tax data (yearly income).
+pub fn calculate(
+    health_insurance_config: &HealthInsuranceConfig,
+    retirement_insurance_config: &RetirementInsuranceConfig,
+    unemployment_insurance_config: &UnemploymentInsuranceConfig,
+    tax_data: &TaxData,
+) -> Result<u32, &'static str> {
+    // for self-employed persons there is a minimum income that needs to be
+    // used for the health insurance calculations in case that the actual
+    // income is lower
+    let income_for_health_insurance = match tax_data.self_employed {
+        true => {
+            let min_income_year = health_insurance_config.min_income * 12.0;
+            tax_data.gross_income.max(min_income_year as u32)
+        }
+        false => tax_data.gross_income,
+    };
+
+    // calculate health insurance based on the given gross income (limited by the maximum configured income value)
+    let health_insurance = calculate_social_insurance(
+        income_for_health_insurance,
+        calculate_health_insurance_premium(health_insurance_config, tax_data),
+        health_insurance_config.max_income,
+    );
+
+    // calculate retirement insurance either from a given fixed value or as percentage from income
+    let retirement_insurance = match tax_data.fixed_retirement {
+        Some(fixed_retirement) => (fixed_retirement * 12) as f32,
+        None => calculate_social_insurance(
+            tax_data.gross_income,
+            calculate_retirement_insurance_premium(retirement_insurance_config, tax_data),
+            retirement_insurance_config.max_income,
+        ),
+    };
+
+    let unemployment_insurance = match tax_data.self_employed {
+        true => 0.0,
+        false => calculate_social_insurance(
+            tax_data.gross_income,
+            unemployment_insurance_config.premium / 2.0,
+            unemployment_insurance_config.max_income,
+        ),
+    };
+
+    println!(
+        "{}, {}, {}",
+        health_insurance, retirement_insurance, unemployment_insurance
+    );
+
+    return Ok((health_insurance + retirement_insurance + unemployment_insurance) as u32);
+}
+
+/// Calculate the social security payment (for one insurance) based on the given yearly income and premium percentage.
+///
+/// The premium is limited by the maximum monthly income value to be considered for the calculation.
+fn calculate_social_insurance(
+    yearly_income: u32, // the yearly income on which the social security payment is calculated
+    premium_percentage: f32, // how much of the income needs to be payed for the insurance
+    max_monthly_value: f32, // the maximum monthly income that is considered for the premium (monthly upper income limit)
+) -> f32 {
+    let effective_income = (yearly_income as f32).min(max_monthly_value * 12.0);
+    return effective_income * premium_percentage;
+}
+
+fn calculate_health_insurance_premium(
+    health_insurance_config: &HealthInsuranceConfig,
+    tax_data: &TaxData,
+) -> f32 {
+    if tax_data.self_employed {
+        return health_insurance_config.premium_general_reduced
+            + health_insurance_config.premium_additional
+            + health_insurance_config.premium_nursing
+            + health_insurance_config.premium_nursing_additional;
+    } else {
+        return (health_insurance_config.premium_general
+            + health_insurance_config.premium_additional
+            + health_insurance_config.premium_nursing)
+            / 2.0
+            + health_insurance_config.premium_nursing_additional;
+    }
+}
+
+fn calculate_retirement_insurance_premium(
+    retirement_insurance_config: &RetirementInsuranceConfig,
+    tax_data: &TaxData,
+) -> f32 {
+    if tax_data.self_employed {
+        return retirement_insurance_config.premium;
+    } else {
+        // the employer is paying half of the premium for an employee
+        return retirement_insurance_config.premium / 2.0;
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::config::create as create_config;
+
+    struct Data {
+        i: u32,
+        o: u32,
+    }
+
+    #[test]
+    fn test_social_security_calculation_2024() {
+        let test_data = vec![
+            Data { i: 12000, o: 2496 },
+            Data { i: 25132, o: 5227 },
+            Data { i: 62100, o: 12916 },
+            Data { i: 90600, o: 15937 },
+            Data { i: 99999, o: 15937 },
+        ];
+
+        test_social_security(&test_data, 2024, false, None);
+    }
+
+    #[test]
+    fn test_social_security_calculation_self_employed_2025() {
+        let test_data = vec![
+            Data { i: 12000, o: 3093 },
+            Data { i: 25128, o: 5188 },
+            Data { i: 62100, o: 12823 },
+            Data { i: 66150, o: 13659 },
+            Data { i: 99999, o: 13659 },
+        ];
+
+        test_social_security(&test_data, 2025, true, Some(0));
+    }
+
+    fn test_social_security(
+        test_data: &Vec<Data>,
+        year: u32,
+        self_employed: bool,
+        fixed_retirement: Option<u32>,
+    ) {
+        let config = create_config(year).unwrap();
+
+        for data in test_data {
+            let tax_data = TaxData {
+                gross_income: data.i,
+                expenses: 0,
+                fixed_retirement: fixed_retirement,
+                self_employed: self_employed,
+                married: false,
+            };
+
+            let result = calculate(
+                &config.health_insurance,
+                &config.retirement_insurance,
+                &config.unemployment_insurance,
+                &tax_data,
+            )
+            .unwrap();
+            assert_eq!(result, data.o);
+        }
+    }
+}
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diff --git a/net_income_germany_cmd/Cargo.toml b/net_income_germany_cmd/Cargo.toml
new file mode 100644
index 0000000..7580bf6
--- /dev/null
+++ b/net_income_germany_cmd/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "net-income-germany-cmd"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+clap = { version = "4.5.4", features = ["deprecated", "derive"] }
+net-income-germany = { path = "../net_income_germany" }
diff --git a/net_income_germany_cmd/src/main.rs b/net_income_germany_cmd/src/main.rs
new file mode 100644
index 0000000..5080154
--- /dev/null
+++ b/net_income_germany_cmd/src/main.rs
@@ -0,0 +1,74 @@
+//! Calculates and displays taxes and social insurances for a given income.
+//!
+//! The minimal command line call needs just the gross income of the year:
+//! ```
+//! $ net-income-germany-cmd --income 80000
+//! ```
+
+use clap::Parser;
+use std::process;
+
+/// Command line arguments of the application.
+#[derive(Parser, Debug)]
+#[command(version, about, long_about = None)]
+struct Args {
+    /// Annual income before taxes, social security and tax-deductible expenses
+    #[arg(short, long)]
+    income: u32,
+
+    /// Tax-deductible expenses
+    #[arg(short, long, default_value_t = 0)]
+    expenses: u32,
+
+    /// Fixed retirement rate (percentage will be calculated if not set)
+    #[arg(short, long)]
+    fixed_retirement: Option<u32>,
+
+    /// Calculate social security and income taxes for a self-employed person
+    #[arg(short, long)]
+    self_employed: bool,
+
+    /// Calculate with tax splitting for a married couple
+    #[arg(short, long)]
+    married: bool,
+
+    /// For which year the taxes should be calculated
+    #[arg(short, long, default_value_t = 2025)]
+    year: u32,
+}
+
+/// Parses command line arguments, calls the net-income-germany crate then for
+/// calculation of the taxes and social security premiums and prints the result
+/// to the standard output.
+fn main() {
+    let args = Args::parse();
+
+    let tax_data = net_income_germany::TaxData {
+        gross_income: args.income,
+        expenses: args.expenses,
+        fixed_retirement: args.fixed_retirement,
+        self_employed: args.self_employed,
+        married: args.married,
+    };
+
+    // create the tax configuration for the given year
+    let config: net_income_germany::config::Config = net_income_germany::config::create(args.year)
+        .unwrap_or_else(|err| {
+            eprintln!("Failed to calculate the taxes: {err}");
+            process::exit(1);
+        });
+
+    // calculate the taxes with the configuration and the given tax data
+    let tax_result = net_income_germany::calculate(&config, &tax_data).unwrap_or_else(|err| {
+        eprintln!("Failed to calculate the taxes: {err}");
+        process::exit(1);
+    });
+
+    println!(
+        "Net income: {}, social security taxes: {}, income taxes: {}, net ratio: {}",
+        tax_result.net_income,
+        tax_result.social_security_taxes,
+        tax_result.income_taxes,
+        1.0 - tax_result.get_tax_ratio()
+    )
+}