Use this calculator to estimate how a balance grows over time with compound interest and optional ongoing contributions.
Inputs
This topic also has a deeper guide and a printable reference pack, so you can move from the live answer into the method, assumptions, and worked examples without leaving the topic cluster.
A practical guide to simple interest, compound growth, present value, future value, and CAGR that explains why money in different time positions cannot be compared honestly until time and compounding are made explicit.
A practical guide to loans and mortgages that explains amortisation, payment structure, interest allocation, and the trade-off between payment size, total interest, and repayment speed.
These are the main values the calculator uses. Keep the units consistent and, where relevant, match the assumptions explained in the related guide.
Unit: GBP
Use the amount already saved or invested at the start of the projection.
Unit: GBP
Enter the amount added each month if you want to include ongoing contributions.
Unit: %
Use the annual growth rate assumption you want the projection to follow.
Unit: years
Set the total projection length in years.
Choose how often the stated annual rate is compounded in the model.
Use this page for savings projections, investing scenarios, and long-term growth estimates built from your own assumptions rather than market forecasts.
The main result shows the ending balance. Supporting figures break out how much came from your own contributions and how much came from growth.
If you start with 10,000, add 200 each month, and apply a 5.5% annual rate for 10 years, the result shows the projected balance together with the total you paid in and the growth earned.
That makes it easier to compare different contribution levels or time horizons without doing the whole projection by hand.
Results follow the mathematics you enter. Real returns, fees, taxes, contribution timing, and market volatility can all change the actual outcome.
No. It simply applies the annual rate and compounding frequency you enter. Use it for planning and comparison, not as a promise of future performance.
Separating contributions from growth makes it easier to see how much of the final value comes from your own deposits and how much comes from compounding.
Calculate what a present amount grows to after the annual rate and time period you enter are applied.
Discount a future amount back to today's terms using the annual rate and time period you enter.
Use the CAGR Calculator to work out cagr from values you control yourself, without baked-in policy assumptions.
Estimate a standard repayment mortgage from property price, deposit, rate, and term with clear monthly costs and supporting figures.