Regular Savings Calculator
Calculate returns on a regular saver account with monthly deposits. See effective vs headline rate.
Last updated: April 2026 · Source: Bank of England
Final Balance after 12 months
£2,466.00
Interest earned: £66.00
Total Deposited
£2,400.00
Interest Earned
£66.00
Effective Return
2.75%
| Month | Deposited | Interest | Balance |
|---|---|---|---|
| 1 | £200.00 | £0.83 | £200.83 |
| 2 | £400.00 | £2.50 | £402.50 |
| 3 | £600.00 | £5.01 | £605.01 |
| 4 | £800.00 | £8.37 | £808.37 |
| 5 | £1,000.00 | £12.57 | £1,012.57 |
| 6 | £1,200.00 | £17.62 | £1,217.62 |
| 7 | £1,400.00 | £23.53 | £1,423.53 |
| 8 | £1,600.00 | £30.29 | £1,630.29 |
| 9 | £1,800.00 | £37.92 | £1,837.92 |
| 10 | £2,000.00 | £46.41 | £2,046.41 |
| 11 | £2,200.00 | £55.77 | £2,255.77 |
| 12 | £2,400.00 | £66.00 | £2,466.00 |
Note: regular saver accounts typically have a 12-month term with a fixed monthly deposit limit (often £25-£500). The effective return on a 12-month regular saver at 5% AER is roughly half the headline rate because you only earn interest on the average balance.
Disclaimer
This calculator is provided for informational purposes only and should not be considered as financial or tax advice. All calculations are performed locally in your browser — no personal data is collected or sent to our servers. Rates and thresholds are sourced from HMRC and GOV.UK and are updated for the current tax year. Always verify results with HMRC or consult a qualified professional before making financial decisions.
How It Works
Regular savings accounts accept fixed monthly deposits (typically £1-£500) and often offer a higher introductory rate than instant-access accounts. Interest calculation differs from lump-sum accounts because each monthly deposit earns interest for a different number of months. The first deposit earns 12 months of interest, the second earns 11 months, and the final deposit earns just 1 month — so the effective return on total deposits is roughly half the headline rate.
The effective AER (Annual Equivalent Rate) accounts for this timing difference. A regular saver advertising 6% where you deposit £200/month totals £2,400 deposited over the year, but the average balance is only about £1,300 (since early deposits are in longer than late ones). Actual interest earned is approximately £78, which is 6% on the average balance but only about 3.25% on the total £2,400 deposited. The calculator shows both the headline rate and the effective return on total contributions.
Monthly vs annual interest crediting affects the compounding. When interest is paid monthly, it begins earning interest immediately (compound interest). When paid annually, the interest sits un-compounded for up to 12 months. The difference is small for regular savers (typically less than £5 on £2,400 at 6%) but becomes meaningful on larger balances and longer terms. The calculator shows both scenarios for transparent comparison.
Regular saver: £300/month at 5.5% for 12 months
- Monthly deposit: £300 for 12 months = £3,600 total deposited
- First deposit earns 12 months interest: £300 x 5.5% = £16.50
- Last deposit earns 1 month interest: £300 x 5.5% / 12 = £1.38
- Total interest over the year: approximately £107 (sum of declining monthly interest)
- Effective return on £3,600 deposited: £107 / £3,600 = 2.97% — roughly half the headline 5.5% rate
Source: Bank of England
Frequently Asked Questions
- What does the Regular Savings Calculator do?
- Calculate returns on a regular saver account with monthly deposits. See effective vs headline rate. All calculations are performed in your browser using official UK rates and thresholds.
- Is this calculator suitable for financial decisions?
- This calculator provides estimates for guidance only. Investment returns are not guaranteed and your capital is at risk. Consider seeking independent financial advice before making investment decisions.
- Are ISA contributions tax-free?
- Yes. The annual ISA allowance for 2025/26 is £20,000. Any interest, dividends or capital gains within an ISA are completely tax-free.