Savings Interest Calculator UK
Estimate how your savings could grow over time with an initial deposit, monthly contributions and an annual interest rate.
Calculator
What this means
Compound interest helps savings grow over time. Regular monthly contributions can significantly increase your final balance.
How to use this calculator
- Enter your starting balance and any monthly deposit.
- Enter the interest rate (AER) and number of years.
- See your projected balance and interest earned.
Worked example
You save £100 a month at 4% for 5 years, starting from £0.
- Each deposit earns compound interest over time.
- Interest is added and then earns interest itself.
You'll see your final balance and how much of it is interest rather than deposits.
Who this is for
- Anyone building up savings over time.
- People comparing savings accounts by AER.
- Anyone setting a long-term savings habit.
How compound interest grows your savings
Compound interest means you earn interest on your interest, so balances grow faster over time. The AER (Annual Equivalent Rate) lets you compare accounts on a like-for-like yearly basis.
Regular monthly deposits, left to compound, can build a meaningful pot. Remember interest may be taxable above your Personal Savings Allowance unless it's held in an ISA.
Frequently asked questions
No. Variable rates can change. This calculator assumes a fixed rate for illustration.
No. Personal Savings Allowance and ISA tax benefits are not modelled here.
Use the AER (Annual Equivalent Rate) shown on your savings account.
AER (Annual Equivalent Rate) shows the interest you'd earn over a year, accounting for how often interest is paid. It's the fairest way to compare savings accounts.
Possibly, if interest exceeds your Personal Savings Allowance (£1,000 for basic-rate, £500 for higher-rate taxpayers). Interest inside an ISA is always tax-free.
Disclaimer
This calculator provides estimates for guidance only. It is not financial, legal or tax advice. Always check official sources or speak to a qualified professional before making decisions.
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