Why compound interest wins
Your interest earns interest. Over decades the curve steepens so sharply that time in the market beats nearly every other input you can control. Start early, keep going, don't touch it.
Free · No signup · UK-friendly
Bold, chunky finance tools for the rest of us.
Free finance calculators, UK-friendly, no signup.
Compound interest, mortgage, savings goals, FIRE number, early mortgage payoff. Every calculator runs in your browser. Nothing saved, nothing tracked.
Five calculators
Pick a tool. Get an answer.
Grow
Compound interest
See what regular contributions turn into over decades.
Open calculatorBorrow
Mortgage
Monthly repayment and total interest for repayment or interest-only mortgages.
Open calculatorTarget
Savings goal
How much a month to hit your number by a date. Or how long at £X a month.
Open calculatorPayoff
Early mortgage payoff
Overpay a bit each month and see the months and interest you save.
Open calculatorFIRE
FIRE number
The pot you need, based on your annual spend and a safe withdrawal rate.
Open calculatorSuggest
Something missing?
These calculators are open source. File an issue or PR.
Open calculatorBuilt on an open source library
Every calculation runs through @jdizm/finance-calculator on npm. Check the maths, fork it, or use it in your own project.