Compound interest calculator
Principal, a fixed annual rate, and an optional contribution at the end of each compounding period.
Free finance calculators that show their working
Tax, retirement, investing, mortgage and currency calculators. Enter your numbers and get results instantly, free and with no sign-up. Every calculator shows its formula and assumptions, so you know where the numbers come from. Region-specific tools are grouped under Tools by region.
General calculators
Mortgage calculator
Monthly repayment, total interest, and a year-by-year amortization.
FIRE and retirement calculator
A savings target from spending and a withdrawal rate, and the years to reach it.
US dividend withholding tax
Gross dividend, US tax withheld, and the yield left for a non-US investor. Hong Kong residents are at the 30% statutory rate.
Currency conversion cost calculator
Mid-market rate, a provider rate or markup, and fees. Shows what you receive and the true cost.
Dollar-cost averaging (DCA) calculator
A regular contribution at a fixed annual return, with an optional fee and the same total invested at the start.
Rent vs buy calculator
Compare buying a home with renting and investing the difference: net worth, break-even year, total costs and a year-by-year table.
Debt payoff calculator
Months to clear one balance, the interest, and a payoff date from the APR and your payment.
APR calculator
Nominal APR and effective annual rate once an upfront fee is included.
Hong Kong
Hong Kong salaries tax 2025/26
Progressive rates, the two-tiered standard rate, allowances, the mandatory MPF cap, and the 2025/26 tax reduction.
Hong Kong MPF calculator
Mandatory employee and employer contributions, the tax-deduction caps, and a projected balance at retirement.
United States
US Take-Home Pay Calculator 2026
Federal income tax, Social Security, Medicare and state tax on a 2026 US salary, with 401(k), HSA, Child Tax Credit and age 65+ deductions, per paycheck and per year.
United Kingdom
UK Take-Home Pay Calculator 2026/27
Income Tax, National Insurance, pension and student loan deductions on a 2026/27 UK salary, with Scottish bands and the £100,000 taper, per year, month and week.
Japan
Japan Take-Home Pay Calculator 2026
Social insurance, income tax after year-end adjustment, and an estimate of resident tax for a 2026 salary in Japan.
Korea
Korea Salary Take-Home Calculator 2026
Pension, health insurance, long-term care, employment insurance, and withholding tax on a 2026 salary in Korea.
Tools by region
Place-specific calculators are grouped by region.
Latest guides
Fixed vs variable-rate mortgage: how much can your payment move?
Fixed vs variable-rate mortgage: what 0.5–2 point moves do to the payment, when a cheaper start stops winning, and how floating plans reset.
Dollar-cost averaging vs lump sum: what the maths and the evidence say
Dollar-cost averaging vs lump sum: how DCA lowers average cost, why positive returns favour investing sooner, and what Vanguard's 2023 study found.
US take-home pay by state 2026: the same $75,000 salary in 14 states
One $75,000 salary in nine no-wage-tax states plus CA, NY, IL, PA, MA: federal and FICA identical, state tax differs. Net by state, with a $150,000 table.
Savings rate and years to financial independence: why saving 50% beats earning more
How savings rate drives years to financial independence under the 4% rule: 10–70% at 3%, 5% or 7% real return, with a worked example from zero.
15 vs 30 year mortgage: what a shorter term really saves (with 20 and 25 years)
15 vs 30 year mortgage (plus 20 and 25): monthly payment, total interest, investing the difference, and prepaying a 30-year loan to finish in about 20.
MPF fund expense ratio (FER) explained: what it includes and what fees cost your retirement pot
What MPF FER includes and excludes, average/high/low by fund type at 31 August 2026, a 35-year fee-gap example, and what the eMPF cut to 0.29% is worth.
HK$320 a month for five years at 4%
HK$320 a month for five years at 4% a year, compounded monthly with deposits at month-end, grows to about HK$21,215.67. That is an illustration, not a promised return.