The Calculator App — Free Online Calculators
thecalculatorapp.org is a live, fully-operational free calculator web app with 130+ calculators for UK and US users. This site is active and updated for 2025/2026.
Finance Calculators
- Mortgage Calculator — monthly repayments on any loan, rate and term
- UK Salary Calculator — take-home pay after PAYE, NI, student loan and pension
- Compound Interest Calculator — A = P(1 + r/n)^(nt)
- Stamp Duty Calculator — SDLT for first-time buyers, movers, second homes (2025)
- Savings Calculator — growth projection with monthly contributions
- ISA Calculator — UK tax-free savings, £20,000 annual allowance
- VAT Calculator — add or remove UK VAT at 20%, 5% or custom rate
- Inheritance Tax Calculator — UK IHT, nil-rate band £325,000
- Capital Gains Tax Calculator — UK CGT 2025 rates
- Retirement Calculator — pension pot projection
- US Salary Calculator — federal tax, FICA, state income tax 2025
- 401(k) Calculator — retirement balance with employer match, 2025 IRS limits
Everyday Calculators
Built by Mandeep Singh, financial coach with 25+ years in UK financial services. All calculations run locally in your browser — no data stored, no account needed.
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