--- title: "Savings Interest Tax Calculator: UK Rates 2026/27" description: "When assessing a client's liability on savings and interest income, advisors rely on specific ordering rules and statutory allowances. If you are asking, \"which tax rate applies? A guide to using a tax calculator interest tool\", you must understand how…" url: "https://www.accountingfirms.co.uk/knowledge-bank/which-tax-rate-applies-a-guide-to-using-a-tax-calculator-interest-tool/" updated: "2026-08-12" category: The tax basics --- # Savings Interest Tax Calculator: UK Rates 2026/27 When assessing a client's liability on savings and interest income, advisors rely on specific ordering rules and statutory allowances. If you are asking, "which tax rate applies? A guide to using a tax calculator interest tool", you must understand how the underlying legislative algorithms process the figures for the 2026/27 tax year. Below is an exhaustive technical breakdown of how to calculate the correct [tax rate](https://www.accountingfirms.co.uk/blog/interesting-dividends/) on interest income, detailing the statutory steps, nil-rate bands, and crucial upcoming reforms for 2027. ## The 7-Step Calculation Framework Any robust [tax calculator](https://www.accountingfirms.co.uk/blog/capital-allowances-whats-new/) interest tool fundamentally mirrors the statutory mechanism outlined in section 23 of the Income Tax Act 2007 (ITA 2007). The Supreme Court in *R v HMRC* confirmed that section 23 provides a strict step-by-step guide to calculating [income tax](https://www.accountingfirms.co.uk/blog/hmrc-payment-niers/) liability. > "Chapter 3, headed 'Calculation of Income Tax Liability' provides in section 23 a step-by-step guide to the process... Step 1 Identify the amounts of income on which the taxpayer is charged to income tax for the tax year... Step 2 Deduct from the components the amount of any relief... The sum of the amounts of the components left after this step is ‘net income’." To determine which rate applies to interest, the tool must first establish the client's ["net income"](https://www.accountingfirms.co.uk/blog/childcare-benefit-and-the-tax-charge/) by stacking savings income on top of non-savings, non-dividend income (like employment or pension income). ## The 2026/27 Income Thresholds Before applying the savings rates, you must establish the client's core tax bands. The government has frozen the primary income thresholds up to and including the 2027/28 tax year. - **Personal Allowance (PA):** Fixed at £12,570. - **Basic Rate Limit:** Fixed at £37,700. - **Higher Rate Threshold:** Fixed at £50,270 (the PA combined with the basic rate limit). ## The Starting Rate for Savings (SSR) Once non-savings income is accounted for, the first layer of interest income may qualify for the starting rate for savings. Under section 12 of the ITA 2007, this provides a 0% tax band for savings income. For the 2026/27 tax year (and frozen until 2030/31), section 9 of the Finance Act 2026 fixes the starting rate limit at £5,000.  However, as established in First-tier Tribunal case law such as *Roger Joye v HMRC*, this nil-rate band inversely tapers against the client's non-savings income. The starting rate for savings is only fully available if the client's total non-savings income is less than their Personal Allowance plus £5,000 (i.e., £17,570).  If the client earns taxable non-savings income above £17,570, they lose the starting rate entirely. ## The Personal Savings Allowance (PSA) The next step in the calculation tool applies the Personal Savings Allowance (PSA) under section 12B of the ITA 2007.  The PSA taxes a specific tranche of interest income at the "savings nil rate" (0%). The exact allowance depends on the client's highest marginal tax band: - **Basic-rate taxpayers:** £1,000 allowance. - **Higher-rate taxpayers:** £500 allowance. - **Additional-rate taxpayers:** Nil allowance. It is critical to note that the PSA and the starting rate are "nil-rate bands" rather than true deductions.  They consume the client's basic or higher rate bands, pushing subsequent income further up the tax brackets. ## The 2026/27 Savings Tax Rates Interest income exceeding the SSR and PSA falls into the chargeable savings tax bands. Section 3 of the Finance Act 2026 sets the savings rates of income tax for the 2026/27 tax year: - **Savings Basic Rate:** 20%. - **Savings Higher Rate:** 40%. - **Savings Additional Rate:** 45%. ## Critical Horizon Planning: The 2027/28 Reforms When forecasting liability, advisors must factor in the severe legislative shifts taking effect on 6 April 2027. Section 5 of the Finance Act 2026 dictates that for the 2027/28 tax year, the savings [tax rates](https://www.accountingfirms.co.uk/blog/badr-the-long-goodbye/) will increase aggressively across the board: the basic rate will rise to 22%, the higher rate to 42%, and the additional rate to 47%. Furthermore, the government is altering the fundamental calculation rules for the allocation of the Personal Allowance. From April 2027, the rules will mandate that reliefs and allowances only apply to property, savings, and dividend income *after* they have been exhausted against other sources of income. ## Summary Table: Taxation of Interest (2026/27) | Element / Band | 2026/27 Rate / Limit | Statutory Authority | | --- | --- | --- | | **Personal Allowance** | £12,570 | Policy Notice [2026-2028] | | **Basic Rate Limit** | £37,700 | Policy Notice [2026-2028] | | **Starting Rate for Savings** | Up to £5,000 at 0% | s. 9 FA 2026  / s. 12 ITA 2007 | | **SSR Income Threshold** | Phased out completely at £17,570 | *Roger Joye v HMRC* | | **Personal Savings Allowance** | £1,000 (Basic) / £500 (Higher) / Nil (Additional) | s. 12B ITA 2007 | | **Savings Basic Rate** | 20% | s. 3(2)(a) FA 2026 | | **Savings Higher Rate** | 40% | s. 3(2)(b) FA 2026 | | **Savings Additional Rate** | 45% | s. 3(2)(c) FA 2026 | *Next steps: Calibrate your tax software to apply the 20% / 40% / 45% savings rates for 2026/27 calculations, and begin communicating the impact of the incoming 22% / 42% / 47% rates for the 2027/28 tax year to highly liquid clients.*