Financial calculators that actually show you the math
Interactive, beautifully charted, and completely private — every number is computed in your browser and never sent anywhere. No sign-up, no paywall, no dark patterns.
Mortgage Calculator
Estimate your monthly mortgage payment, see how principal and interest shift over time, and find out how much extra payments save you — all computed in your browser.
Loan Calculator
Calculate the monthly payment and total interest on an auto or personal loan, and compare how different terms change the cost.
Retirement Calculator
Project how your savings could grow with compound returns and regular contributions — including an uncertainty range, not just a single optimistic line.
Income Tax Calculator
Estimate your UK income tax by band and see why your effective rate is lower than your top marginal rate. Amounts are shown in £.