See how savings and investments grow with compound interest, including regular monthly contributions.
Savers and investors projecting how their money grows over time.
Enter your starting amount
Type the initial principal you are saving or investing.
Add rate, years, and contributions
Set the annual interest rate, the number of years, and any regular monthly contribution.
Choose compounding frequency
Pick how often interest compounds (e.g. monthly or annually), then read the final balance and total interest earned.
Compound interest is the engine behind long-term saving and investing: you earn interest not just on your original deposit but on all the interest it has already earned, so the balance grows faster and faster over time. The effect is hard to picture in your head — the difference between a 5% and 7% return, or saving for 20 years versus 30, is far larger than it intuitively feels — which is exactly why seeing it projected makes the case for starting early so compelling. This calculator projects that growth clearly. Enter a starting amount, an annual rate, a number of years, and any regular monthly contribution, choose how often interest compounds, and it shows your final balance and the total interest earned. It is built for understanding and goal-setting — comparing rates, terms, and contribution levels side by side. It runs in your browser with nothing stored, and it is an illustration only: it does not account for tax, fees, or inflation, so treat the figures as a model rather than a promise.
Retirement planning
Project how a pension or long-term investment could grow over decades of contributions.
Savings goals
See how regular monthly deposits build toward a target like a house deposit or fund.
Comparing accounts
Compare how different rates and compounding frequencies change the end result.
Teaching & learning
Show, with real numbers, why starting to save earlier beats saving more later.
Debt awareness
Understand how compounding also works against you on interest-bearing debt.
Simple interest is earned only on the principal; compound interest is earned on the principal plus previously earned interest, so the balance grows faster over time.
More frequent compounding (e.g. monthly vs annually) earns slightly more, because interest is added — and starts earning — sooner.
Yes. Regular monthly contributions are added and compounded alongside your starting balance.
No. It shows gross growth only. Real returns are reduced by tax and fees, and inflation lowers future purchasing power.
Use a realistic expected annual return for your account or investment; try a range to see best- and worst-case projections.
That is compounding: the bigger the balance, the more interest it earns each period, so growth accelerates toward the end of the term.
No. It is an estimate for illustration only — consult a qualified adviser for decisions.
Yes — free, runs in your browser, no sign-up.