Tax Calculators
Estimators for equity compensation, self-employment, and withholding, with every statutory figure sourced and dated.
- Autónomo Quarterly Tax Calculator (Modelo 130)Calculate your Spain autónomo quarterly IRPF advance payment (Modelo 130). Enter quarterly income, expenses, and prior payments to get the exact amount due.
- Capital Gains Holding Period CalculatorSee the tax difference between selling now at short-term rates versus waiting for long-term capital gains treatment, including the NIIT surcharge.
- Dependent Care FSA vs Child & Dependent Care CreditCompare the pre-tax Dependent Care FSA payroll deduction to the Child and Dependent Care Credit to find which saves you more — or how to stack both.
- Effective vs Marginal Tax Rate CalculatorSee your effective (average) and marginal federal income tax rates side by side, with a bracket-by-bracket breakdown, using 2025 IRS rate schedules.
- German Income Tax Calculator 2025Calculate your German Einkommensteuer 2025. Enter gross salary to get income tax, Solidaritätszuschlag, social security contributions, and net pay.
- ESPP Qualifying vs Disqualifying Disposition CalculatorCompare the after-tax proceeds of a qualifying vs disqualifying ESPP sale and see exactly how much the holding period is worth.
- HSA Triple-Tax-Benefit CalculatorCalculate the combined upfront deduction, tax-free growth, and tax-free withdrawal advantage of an HSA versus a taxable investment account.
- Spain IRPF Income Tax CalculatorCalculate your Spain IRPF income tax (2025). Enter gross salary to get tax payable, effective rate, and monthly net pay including Social Security deductions.
- ISO AMT Exposure CalculatorEstimate the Alternative Minimum Tax you may owe when exercising Incentive Stock Options, including the AMT preference item, tentative minimum tax, and AMT credit carryforward.
- IVA CalculatorCalculate Spanish IVA (VAT) at 21%, 10%, or 4%. Get the tax amount and total price from any base price instantly.
- Pay Stub Calculator — Net Pay After TaxesCalculate your net take-home pay per paycheck after federal income tax, Social Security, Medicare, and pre-tax deductions.
- RSU Vesting Tax EstimatorEstimate the tax owed when restricted stock units vest, how much your employer withholds, and the shortfall you must cover.
- Spain Social Security CalculatorCalculate Spain Social Security (Seguridad Social) contributions for employees and autónomos (RETA). See employee, employer, and total cost for 2025.
- Self-Employment Quarterly Tax EstimatorEstimate quarterly estimated tax payments for freelance and 1099 income, including self-employment tax and safe-harbour targets.
- State Income Tax Calculator 2025Estimate your state income tax for any US state in 2025. Enter your gross income and state tax rate to see your estimated state tax, effective rate, and monthly impact.
- Tax-Loss Harvesting Benefit CalculatorQuantify the tax benefit of harvesting a capital loss today versus holding the position, net of any tracking-error drag from a substitute investment.
- W-4 Withholding EstimatorCalculate your federal income tax withholding and estimate your tax refund or balance due based on your W-4.
Tax guides
- Why RSU Withholding Leaves You With a Tax BillSupplemental wage withholding on RSUs is a flat statutory rate, not your marginal rate. Here is where the gap comes from and how to close it.
- How to Read Your Pay StubEvery line on a pay stub explained: gross pay, federal and state withholding, FICA, pre-tax deductions, and why your net pay is lower than you expected.