Compound Interest Calculator UK
This compound interest calculator helps you estimate how savings or investments could grow over time in the UK. You can model an initial balance, interest rate, compounding frequency, regular contributions, withdrawals and annual increases to build a clearer long-term projection.
It is useful for anyone comparing savings plans, investment scenarios or future-value estimates and wanting to see how compounding may affect the final balance over months and years.
What this calculator includes
- Initial lump sum or starting balance
- Annual interest or growth rate
- Monthly, quarterly or annual compounding
- Regular contributions with optional yearly increases
- Regular withdrawals with optional yearly increases
- Projected balance, growth, deposits and withdrawals
- Chart and yearly breakdown to help visualise the outcome
How it works
The calculator applies your chosen annual rate over the selected time period using the compounding frequency you choose. It then adds any regular contributions and subtracts any regular withdrawals so you can see the combined effect on your balance. This makes it useful for both a simple compound interest estimate and more realistic savings planning.
Why results may vary
Real-world results may differ from the illustration because actual savings and investment returns are rarely fixed. Fees, tax, inflation, market volatility, account rules and the timing of contributions or withdrawals can all change the outcome. That is especially important if you are using the calculator for investing rather than cash savings.
Who it's for
- Savers building a long-term pot with monthly contributions
- Investors estimating potential future value
- People comparing different interest rates or contribution levels
- Anyone modelling withdrawals for medium- or long-term planning
Compound interest examples
- £5,000 at 5% for 10 years with no contributions
- £10,000 with £200 monthly contributions over 20 years
- £50,000 with regular withdrawals to test drawdown sustainability
- Comparing monthly versus annual compounding on the same rate
Important note
This calculator provides estimates only and does not constitute financial, tax or legal advice. Use it as a planning tool, not as a guarantee of future returns or account performance.
Use the calculator above to compare scenarios, test different contribution levels and see how compound growth could affect your future balance.