ISA Calculator 2025/26
Calculate tax-free growth for UK Individual Savings Accounts. The annual ISA allowance for 2025/26 is £20,000. All growth within an ISA is completely tax-free.
£
£
%
years
Results
Final balance£256,824
Total deposited£200,000
Total interest earned£56,824
Final balance£256,824
Balance breakdown
Total deposits£200,000
Interest earned£56,824
Growth over time
DepositsInterest
Year-by-year breakdown
| Year | Opening | Deposited | Interest | Closing |
|---|---|---|---|---|
| 1 | £0.00 | £20,000.00 | £900.00 | £20,900.00 |
| 2 | £20,900.00 | £20,000.00 | £1,840.50 | £42,740.50 |
| 3 | £42,740.50 | £20,000.00 | £2,823.32 | £65,563.82 |
| 4 | £65,563.82 | £20,000.00 | £3,850.37 | £89,414.19 |
| 5 | £89,414.19 | £20,000.00 | £4,923.64 | £114,337.83 |
| 6 | £114,337.83 | £20,000.00 | £6,045.20 | £140,383.04 |
| 7 | £140,383.04 | £20,000.00 | £7,217.24 | £167,600.27 |
| 8 | £167,600.27 | £20,000.00 | £8,442.01 | £196,042.28 |
| 9 | £196,042.28 | £20,000.00 | £9,721.90 | £225,764.19 |
| 10 | £225,764.19 | £20,000.00 | £11,059.39 | £256,823.58 |
Starting with a Cash ISA balance of £0 and depositing £20,000 per year at 4.5% interest over 10 years, your ISA would grow to £256,824. You would have deposited £200,000 in total and earned £56,824 in tax-free interest.