Answers · UK 2025/26

How much difference does monthly versus annual compounding make on £10,000 of savings?

Only a few pounds a year at typical rates. On £10,000 at 5%, annual compounding gives £500 of interest in year one, while monthly compounding gives about £511.62 - roughly £11.62 more. The gap widens slightly over many years but stays small at ordinary savings rates.

Last updated: 10 June 2026Last reviewed: 10 June 2026How we verify

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Compounding frequency affects how often interest is added back to your balance so it can earn interest itself, but at normal savings rates the difference is modest. Worked example on £10,000 at a 5% advertised rate over one year: with annual compounding you get a flat £500, ending at £10,500. With monthly compounding the rate is applied as roughly 0.4167% each month on the growing balance, producing about £511.62 of interest, ending at £10,511.62 - around £11.62 more. This is why banks quote the AER (Annual Equivalent Rate), which standardises returns so you can compare accounts regardless of how often they compound. Over longer periods the effect grows but remains small at these rates: £10,000 at 5% for 10 years is about £16,289 with annual compounding versus roughly £16,470 with monthly, a difference under £200. Higher rates and longer terms widen the gap, which is why compounding matters far more in long-term investments than in short-term savings. Tax also matters: outside an ISA a higher-rate taxpayer loses 40% of interest above the £500 Personal Savings Allowance, which dwarfs any compounding-frequency benefit, so using your £20,000 ISA allowance is usually the bigger lever. Use the compound interest calculator to compare frequencies and the savings calculator to factor in tax. For the AER definition and savings tax rules, see gov.uk.