Every figure on this site is built from published UK government rates for the 2026/27 tax year and checked against primary sources. This page sets out exactly which rates, thresholds and formulas we use, with links to verify each one, plus the assumptions and limits of every calculator. Nothing here is hidden — if a number looks wrong to you, you can trace it.
We take rates from official publications, not third-party summaries. The figures below are drawn from and can be verified against:
Tax is applied in bands to your income above the Personal Allowance. The allowance is £12,570, but it tapers away once adjusted net income passes £100,000 (you lose £1 of allowance for every £2 over the limit, so it's gone by £125,140 — the cause of the well-known 60% effective rate in that band).
| Band | Taxable income | Rate |
|---|---|---|
| Personal Allowance | £0 – £12,570 | 0% |
| Basic rate | £12,571 – £50,270 | 20% |
| Higher rate | £50,271 – £125,140 | 40% |
| Additional rate | Over £125,140 | 45% |
Scottish taxpayers have their own bands and rates (set by the Scottish Parliament), though the Personal Allowance and its taper are the same UK-wide. National Insurance is also UK-wide. For 2026/27:
| Band | Gross income | Rate |
|---|---|---|
| Starter rate | £12,571 – £16,537 | 19% |
| Basic rate | £16,538 – £29,526 | 20% |
| Intermediate rate | £29,527 – £43,662 | 21% |
| Higher rate | £43,663 – £75,000 | 42% |
| Advanced rate | £75,001 – £125,140 | 45% |
| Top rate | Over £125,140 | 48% |
National Insurance applies UK-wide on earnings above the Primary Threshold of £12,570:
| Earnings | Rate |
|---|---|
| Up to £12,570 | 0% |
| £12,570 – £50,270 | 8% |
| Over £50,270 | 2% |
We annualise NI for clarity. In reality it's worked out per pay period, so a one-off bonus can attract slightly more NI in the month it's paid than our annual figure implies. Those over State Pension age pay no NI on earnings.
You repay a percentage of income above your plan's threshold. Interest is set against RPI (3.2% for the year to 31 August 2026), with Plan 2 and Postgraduate loans capped at 6% from September 2026 and sliding with income. Any balance left after the write-off period is cancelled.
| Plan | Threshold | Repay | Interest | Written off |
|---|---|---|---|---|
| Plan 1 | £26,900 | 9% | ~3.2% | 25 yrs / age 65 |
| Plan 2 | £29,385 | 9% | RPI–6% | 30 yrs |
| Plan 4 | £33,795 | 9% | ~3.2% | 30 yrs |
| Plan 5 | £25,000 | 9% | ~3.2% | 40 yrs |
| Postgraduate | £21,000 | 6% | ~6% | 30 yrs |
Repayments in the take-home calculators are based on gross income. The overpayment tool projects the loan year by year to show whether you'd clear it before write-off — the only situation in which overpaying saves money.
Child Benefit is £27.05/week for the eldest or only child and £17.90/week for each additional child. The High Income Child Benefit Charge claws it back at 1% for every £200 of adjusted net income above £60,000, reaching 100% at £80,000. Crucially, the charge is assessed on the higher earner's individual income, not the household total — which is why our household calculator treats two incomes separately.
Statutory Maternity Pay runs for up to 39 weeks: 90% of your average weekly earnings for the first 6 weeks, then the lower of £194.32 or 90% of earnings for up to 33 more weeks. You must earn at least £129/week on average to qualify. Statutory Sick Pay is £123.25/week for up to 28 weeks. Both are shown gross (Income Tax and NI still apply) and before any enhanced employer scheme.
Take-home pay. We apply the Personal Allowance (tapered if needed), tax the remainder band by band, add National Insurance and any student loan, and subtract pension contributions according to the scheme type you choose:
Adjusted net income — used for both the Personal Allowance taper and the Child Benefit charge — is gross pay minus pension and any salary sacrifice.
Mortgages and loans use the standard amortisation formula, where r is the monthly rate and n the number of months: monthly payment = P · r · (1+r)ⁿ ÷ ((1+r)ⁿ − 1). Investment growth compounds monthly. Debt vs invest runs both choices over an identical monthly budget and time horizon — the two tie exactly when your investment return equals the debt's interest rate, which is the principle behind the decision.
Worked example — £45,000 salary, 5% salary-sacrifice pension, rest of UK, 2026/27:
UK tax rates and thresholds change every April, and student-loan interest is reset each September. We review and update every rate at the start of each tax year and whenever the government announces a change, and we keep the previous year's figures so the year-comparison tool stays accurate. Every page shows the tax year it applies to.
This page was last reviewed on 2 June 2026 for the 2026/27 tax year.
Every calculation runs entirely in your own browser using JavaScript. Your salary and personal figures are never sent to us or to any server — there is nothing to store and nothing to leak. You can use the site offline once it has loaded.