If you are comparing savings accounts and want to know how much your money might grow, this UK interest rate savings calculator gives you a fast estimate. Enter your starting amount, monthly savings, AER, and term to see projected balance, interest, estimated tax, and inflation-adjusted value.
UK Savings Interest Calculator
Estimate the future value of your savings with compound interest.
Estimate only. Real account rules, promotional rates, and tax treatment can differ.
How this UK savings calculator works
This tool uses compound interest to project your balance. It assumes the interest rate remains constant for the full term and that your monthly savings continue at the same level. In reality, UK savings rates can move up or down over time, so treat the result as a planning estimate rather than a guaranteed return.
- Initial savings: the amount you start with today.
- Monthly contribution: your regular deposit each month.
- AER: annual equivalent rate, commonly shown by UK banks.
- Term: the number of years you expect to save.
- Tax band and ISA: used to estimate net interest after tax.
- Inflation: gives a rough “today’s money” value of your final amount.
AER vs gross interest in UK accounts
Most UK savings products advertise AER, which standardises rates across different compounding schedules. That makes it easier to compare accounts. AER already reflects compounding, while a gross rate may not. If you are entering a number from a UK account page, AER is usually the best input.
Why compounding frequency still matters
Although AER is standardised, some accounts compound monthly, quarterly, or annually. This calculator lets you select frequency so you can test different assumptions and model accounts with varying payout methods.
Tax on savings interest in the UK
Outside tax wrappers like a Cash ISA, savings interest can be taxable depending on your total income and your personal savings allowance (PSA). This calculator includes a simple estimate using your selected tax band and PSA settings:
- Basic-rate taxpayers: PSA typically £1,000 per tax year.
- Higher-rate taxpayers: PSA typically £500 per tax year.
- Additional-rate taxpayers: PSA typically £0.
If your savings are inside a Cash ISA, interest is usually tax free. Tick the ISA option in the calculator to remove estimated tax from projections.
Tips to improve your savings return
- Automate monthly deposits so contributions happen before spending decisions.
- Review rates every few months and switch when fixed terms end.
- Use tax wrappers such as Cash ISA allowances where suitable.
- Separate emergency savings from medium-term goals to choose better products for each.
- Increase contributions after pay rises; even small increases compound over time.
Example scenario
Suppose you start with £5,000, add £200 per month, and earn 4.5% AER for 10 years. Your final balance could be significantly higher than the amount you paid in, because interest is earned on both your contributions and past interest. If inflation runs at 2.5%, your inflation-adjusted purchasing power will be lower than the headline balance, which is why it is useful to review both figures.
Frequently asked questions
Is this calculator for regular saver accounts?
Yes, it can model regular saving behaviour, though some regular saver products have contribution caps or special rules that this estimate does not enforce.
Does this replace financial advice?
No. It is a planning tool for education and comparison. For major decisions, especially tax-sensitive ones, consider regulated financial advice.
Can I use it for fixed-rate bonds?
Yes. Set monthly contribution to £0 if you are investing a lump sum only, then enter the term and expected annual rate.