Calculators
Three free calculators for the arithmetic behind saving and debt. Each page writes down its assumptions, shows a worked example you can read without JavaScript, and recalculates when you change the numbers.
Tools
- Compound interest calculatorEnding balance, money put in, and interest, from a starting amount and a monthly deposit compounded monthly.
- Savings goal calculatorThe monthly deposit that reaches a target, given what you have saved, a rate, and a deadline.
- Debt payoff calculatorHow long one balance takes to clear at a fixed payment, and what paying extra each month changes.
Compound is a financial-education app: short daily lessons and a $10,000 paper-trading portfolio that uses simulated money. These calculators are the formulas those lessons talk about. The guides linked below are the lessons themselves, in plain HTML.
Learn the ideas behind the formulas
Short daily lessons on saving, credit, investing, and taxes, plus a $10,000 paper-trading portfolio. Free to start. No real trades and no brokerage account.
Start learning free