Factual information only. Nothing here is financial advice.
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We're building the full comparison: savings, ISAs, NS&I and gilts, ranked by the return you actually keep.
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Uses 2026/27 tax rates for England, Wales & Northern Ireland — Scottish income tax differs.
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Tax on your next £1 of interest
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Personal Savings Allowance left
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ISA allowance left this year
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Interest inside an ISA is tax-free
Access term
Listed market-wide, sorted by estimated after-tax return, highest first — all rows use the same assumptions. Sort order is not a recommendation. Tap a row for the working.
Return you keepLost to tax
Rates used in this comparison
Tracked automatically from official sources — Bank of England, NS&I, DMO · snapshot 17 July 2026. Market averages can differ from your account — switch to Manual for your exact rates.
Enter the rates you're actually offered — figures update instantly.
Methodology & assumptions
English/Welsh/NI income tax rates and bands for 2026/27; personal allowance £12,570, tapered £1 per £2 of income over £100,000; higher-rate threshold £50,270; additional rate above £125,140. Source: gov.uk — Income Tax rates
Interest is taxed as savings income: 0% starting rate on up to £5,000 (low earners), then the Personal Savings Allowance (£1,000 basic rate / £500 higher / £0 additional), then your marginal rate. gov.uk — Tax on savings interest
Gilt coupons are taxable as savings income; gilt capital gains are exempt from Capital Gains Tax (TCGA 1992 s.115). Gilt gains here are annualised straight-line to maturity, held to redemption. DMO
ISA interest and Premium Bonds prizes are tax-free. Premium Bonds figures use the published prize fund rate — the long-run average; a typical holder wins slightly less than average in any year (prizes are a lottery). NS&I rates
Savings rates shown are Bank of England market averages unless a specific product is named — your account may pay more or less; edit the rates above to match. Bank of England
Pension contributions entered are treated as relief-at-source: grossed up by 25%, extending your basic-rate band and reducing adjusted net income.
Multi-year fixed bonds where interest is only accessible at maturity are shown with tax spread annually for comparability; in practice HMRC may tax all the interest in the maturity year, which can use more of your allowances at once. This is flagged on the affected rows.
All outputs are estimates based on the rates snapshot dated above.