README

A framework-agnostic PHP 8.4+ library for calculating Dutch income tax, social security contributions and tax credits. This package is a modern PHP implementation based on the dutch-tax-income-calculator-npm package.

Features

• Payroll Tax (Loonbelasting) calculation
• Social Security Contributions (Volksverzekeringen - AOW, Anw, Wlz)
• General Tax Credit (Algemene Heffingskorting)
• Labour Tax Credit (Arbeidskorting)
• Elder Credit (for retirement age workers)
• 30% Ruling (30%-regeling) for expats
• Holiday Allowance (Vakantiegeld - 8%)
• Support for tax years 2015-2026
• Framework-agnostic - works with Laravel, Symfony or any PHP project

Requirements

• PHP 8.4 or higher

Installation

composer require fiscfree/dutch-tax-income-calculator

Quick Start

<?php

use DutchTaxCalculator\DutchTaxCalculator;
use DutchTaxCalculator\DTO\SalaryInput;
use DutchTaxCalculator\Enum\Period;

$calculator = new DutchTaxCalculator();

$result = $calculator->calculate(
    input: new SalaryInput(
        income: 60000.00,
        includeHolidayAllowance: true,
        socialSecurity: true,
        reachedRetirementAge: false,
        hoursPerWeek: 40.0
    ),
    period: Period::Year,
    year: 2026
);

echo "Gross yearly: " . $result->grossYear . "\n";
echo "Net yearly: " . $result->netYear . "\n";
echo "Net monthly: " . $result->netMonth . "\n";
echo "Income tax: " . $result->incomeTax . "\n";
echo "Effective tax rate: " . $result->effectiveTaxRate . "%\n";

Usage Examples

Basic Calculation

use DutchTaxCalculator\DutchTaxCalculator;
use DutchTaxCalculator\DTO\SalaryInput;
use DutchTaxCalculator\Enum\Period;

$calculator = new DutchTaxCalculator();

// Calculate from monthly salary
$result = $calculator->calculate(
    input: new SalaryInput(income: 5000.00),
    period: Period::Month,
    year: 2026
);

// Access results
$result->grossYear;      // Annual gross income
$result->grossMonth;     // Monthly gross income
$result->netYear;        // Annual net income
$result->netMonth;       // Monthly net income
$result->incomeTax;      // Total income tax (negative)
$result->payrollTax;     // Payroll tax (negative)
$result->socialTax;      // Social security (negative)
$result->labourCredit;   // Labour credit (positive)
$result->generalCredit;  // General credit (positive)

With 30% Ruling

use DutchTaxCalculator\DutchTaxCalculator;
use DutchTaxCalculator\DTO\SalaryInput;
use DutchTaxCalculator\DTO\RulingOptions;
use DutchTaxCalculator\Enum\Period;
use DutchTaxCalculator\Enum\RulingType;

$calculator = new DutchTaxCalculator();

// Using factory method (recommended)
$result = $calculator->calculate(
    input: new SalaryInput(income: 80000.00),
    period: Period::Year,
    year: 2026,
    ruling: RulingOptions::enabled()  // or enabled(RulingType::YoungMaster)
);

// Or using constructor
$result = $calculator->calculate(
    input: new SalaryInput(income: 80000.00),
    period: Period::Year,
    year: 2026,
    ruling: new RulingOptions(
        enabled: true,
        type: RulingType::Normal  // Normal, YoungMaster or Research
    )
);

echo "Tax-free amount: " . $result->taxFreeYear . "\n";
echo "Tax-free percentage: " . $result->taxFreePercent . "%\n";

Different Input Periods

// From yearly salary
$calculator->calculate(
    input: new SalaryInput(income: 60000.00),
    period: Period::Year,
    year: 2026
);

// From monthly salary
$calculator->calculate(
    input: new SalaryInput(income: 5000.00),
    period: Period::Month,
    year: 2026
);

// From weekly salary
$calculator->calculate(
    input: new SalaryInput(income: 1154.00),
    period: Period::Week,
    year: 2026
);

// From hourly rate
$calculator->calculate(
    input: new SalaryInput(income: 28.85, hoursPerWeek: 40.0),
    period: Period::Hour,
    year: 2026
);

Retirement Age Workers

$result = $calculator->calculate(
    input: new SalaryInput(
        income: 50000.00,
        reachedRetirementAge: true  // No AOW contribution
    ),
    period: Period::Year,
    year: 2026
);

Without Social Security

$result = $calculator->calculate(
    input: new SalaryInput(
        income: 50000.00,
        socialSecurity: false  // No volksverzekeringen
    ),
    period: Period::Year,
    year: 2026
);

Result Object

The PaycheckResult object provides comprehensive access to all calculated values:

Framework Integration

Laravel

Register as a singleton in a service provider:

// AppServiceProvider.php
public function register(): void
{
    $this->app->singleton(
        \DutchTaxCalculator\DutchTaxCalculator::class,
        fn() => new \DutchTaxCalculator\DutchTaxCalculator()
    );
}

Symfony

Define as a service:

# services.yaml
services:
    DutchTaxCalculator\DutchTaxCalculator: ~

Supported Tax Years

The calculator supports tax years 2015-2026. Tax data is sourced from official Belastingdienst publications.

$calculator->getSupportedYears();  // [2015, 2016, ..., 2026]
$calculator->getCurrentYear();     // 2026
$calculator->isYearSupported(2025); // true

Development

# Install dependencies
composer install

# Run tests
composer test

# Run static analysis
composer phpstan

# Fix code style
composer cs-fix

Testing

The calculator is tested against official Belastingdienst tax tables for all supported years:

vendor/bin/phpunit

References

• Rekenvoorschriften voor de geautomatiseerde loonadministratie
• Loonbelastingtabellen
• 30%-regeling

Credits

• Original JavaScript implementation: dutch-tax-income-calculator-npm
• Tax data source: Belastingdienst

License

MIT License - see LICENSE file for details.