Free interest savings calculator — see how compound interest grows your money
Our free savings calculator projects your savings balance with compound interest and regular contributions. Whether you need an interest savings calculator to see how much interest your money earns, a compound savings calculator for long-term planning, or a retirement savings planner, this tool gives you a clear year-by-year breakdown of contributions versus interest earned. Enter your initial deposit, monthly contributions, and interest rate for instant results.
| Year | Balance | Interest That Year | Total Deposited |
|---|
A common guideline is to save at least 20% of your take-home pay (the 50/30/20 rule). Use the calculator to work backwards — enter your savings goal and target date, then adjust the monthly contribution until the projected balance matches your goal.
Interest is added to your balance each period, and in future periods you earn interest on that interest too. This compounding effect means your savings accelerate over time. Starting early is the biggest factor — even small amounts grow significantly over 20–30 years.
UK easy-access savings accounts in 2025 offered around 4–5% AER, while fixed-rate bonds paid slightly more. ISA rates were similar. In the USA, high-yield savings accounts offered 4–5% APY. Rates change frequently, so check current offers from your bank.
AER (Annual Equivalent Rate) is used for savings accounts and shows the interest you'd earn over a year, factoring in compounding. APR (Annual Percentage Rate) is used for borrowing and includes fees. For savings, always compare AER figures.
A common rule of thumb is to save 25× your expected annual retirement spending (the "4% rule"). For example, if you plan to spend £30,000 per year, you'd target a £750,000 retirement pot. Use the savings calculator to project how long it will take to reach a target amount.
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