See exactly how your money will grow over time. Enter a starting balance, interest rate, compounding frequency, and any regular contributions — then watch projected growth update instantly. Powered entirely in your browser, no data ever leaves your device.
Open Calculator → free, no sign-inA savings calculator answers the most important financial question most people never think to ask: "If I leave this money alone and keep adding to it, what will I have in ten years?" The answer is almost always more surprising — and more motivating — than you'd expect.
Compound interest means you earn interest on your interest, not just your original deposit. A savings account earning 5% annually doesn't just add 5% of your initial deposit each year — it adds 5% of everything that's accumulated. Over long timeframes, this creates exponential growth that dramatically outperforms a simple mental calculation.
This calculator models exactly that: starting balance, annual interest rate, compounding frequency, regular monthly contributions, and time horizon. It shows year-by-year projected balance so you can see growth over time rather than just a final number.
For long-term investment modelling (stocks, index funds), a common assumption is 7–10% nominal annual return. For cash savings accounts, check the current rate your bank offers.
See the full growth curve, not just a final number. Most simple savings calculators show you a single end value. This tool shows year-by-year balance, which makes the compounding effect visible — you can see the curve steepen as accumulated interest grows large enough to generate meaningful returns on its own.
Model regular contributions alongside compound interest. A starting balance alone doesn't capture how most people actually save. Adding a monthly contribution dramatically changes the trajectory. Experimenting with different amounts — £100/month vs. £200/month — instantly shows the 10- or 20-year difference.
Your financial data never leaves your device. This tool runs entirely in your browser. There's no backend server receiving your numbers. Your balance, rate, and contribution amounts stay local and disappear when you close the tab.
What is compound interest?
Compound interest means you earn interest on your accumulated balance — not just your original deposit. Interest earned in month one becomes part of the balance that earns interest in month two, creating exponential growth over time.
What compounding frequency should I use?
Match it to your account. Most savings accounts compound monthly or daily. For investments (index funds, pensions), annual compounding is a reasonable approximation. The difference between monthly and daily compounding is small for most rates.
Can I use this for ISAs, 401(k)s, or index funds?
Yes. Enter your expected annual return rate and use annual compounding. Common long-term stock market assumptions are 7–10% nominal annual returns, though actual results vary and past performance doesn't guarantee future results.
Does it account for inflation?
The calculator shows nominal values. To estimate real purchasing power, subtract your expected inflation rate from the interest rate. For example, if you expect 5% returns and 2.5% inflation, enter 2.5% as your rate to see real growth.
How much do I need to save monthly to reach a goal?
Experiment with the monthly contribution field and time horizon until the projected balance reaches your target. Try halving and doubling the contribution to understand the sensitivity before committing to a savings plan.
Is my financial data stored anywhere?
No. All calculations happen in your browser. Nothing is sent to a server, stored in a database, or used for any purpose. Your numbers disappear when you close the tab.
Free. Instant. No sign-in. Enter your numbers and see exactly what you'll have.
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