How we calculate
Every rate we use, where it came from, what the calculators include, and what they deliberately do not.
Tax year
We are on 2026/27
The UK tax year runs 6 April 2026 to 5 April 2027. Every calculator on this site uses that year unless the page says otherwise.
The rates
Income tax
| Band | Taxable income | Rate |
|---|---|---|
| Personal Allowance | Up to £12,570 | 0% |
| Basic rate | £12,571 to £50,270 | 20% |
| Higher rate | £50,271 to £125,140 | 40% |
| Additional rate | Over £125,140 | 45% |
The Personal Allowance falls by £1 for every £2 of adjusted net income above £100,000, reaching zero at £125,140.
Scotland
| Band | Income | Rate |
|---|---|---|
| Starter | £12,571 to £16,537 | 19% |
| Basic | £16,538 to £29,526 | 20% |
| Intermediate | £29,527 to £43,662 | 21% |
| Higher | £43,663 to £75,000 | 42% |
| Advanced | £75,001 to £125,140 | 45% |
| Top | Over £125,140 | 48% |
National Insurance and other rates
| Item | Threshold | Rate |
|---|---|---|
| Employee Class 1 | £12,570 to £50,270 | 8% |
| Employee Class 1, above UEL | Over £50,270 | 2% |
| Employer Class 1 | Over £5,000 | 15% |
| Blind Person’s Allowance | — | £3,250 |
| Marriage Allowance | — | £1,260 transferable |
| Student loan Plan 1 | £26,900 | 9% |
| Student loan Plan 2 | £29,385 | 9% |
| Student loan Plan 4 | £33,795 | 9% |
| Student loan Plan 5 | £25,000 | 9% |
| Postgraduate loan | £21,000 | 6% |
Sources
Where these come from
Rates and thresholds
Allowances
Method
How a calculation runs
Salary sacrifice comes off first
Salary sacrifice pension and childcare vouchers reduce gross pay before anything else, so they cut both tax and National Insurance.
Then taxable pay is worked out
Net pay pension contributions and other pre-tax deductions come off. Taxable benefits in kind are added on.
Allowances, then bands
Your allowance is set by your tax code if you give one, otherwise from your circumstances with the £100,000 taper applied. Tax is then charged band by band.
NI and student loan use NI-able pay
Both are charged on pay after salary sacrifice but before net pay pension, which is how payroll does it.
Relief at source is handled properly
A personal pension paid from take-home gets 25% added by the provider. If you are a higher-rate taxpayer the extra 20% relief is applied by widening your basic rate band, not by a flat deduction. That is why the three pension types give three different answers.
Checking
How we know the engine is right
Before any calculator goes live, its output at standard salaries is compared against the figures published by several independent UK calculators. At the time of writing the engine matches on every test:
| Salary | Our take-home | Published elsewhere |
|---|---|---|
| £40,000 | £32,320 (£2,693 a month) | £32,320 (£2,693 a month) |
| £50,000 | £39,520 | £39,520 |
| £120,000 | tax of £39,432 | tax of £39,432 |
Limits
What the calculators do not do
These are real limits, not disclaimers. Knowing them is the difference between a useful estimate and a wrong one.
Annual, not per pay period. Real payroll works month by month on a cumulative basis. Our figures are annual and divided down. If your pay changes mid-year, or you started a job part way through, your payslip will differ.
No savings, dividend or rental income. The calculators cover employment and pension income only.
No Self Assessment. Payments on account, capital gains, the High Income Child Benefit Charge and pension annual allowance charges are all outside scope.
Tax codes are applied simply. A W1 or M1 code is treated as cumulative. Real emergency-code payroll does not work that way.
Salary sacrifice has rules we do not police. You cannot sacrifice below minimum wage, and we do not check that for you.
Student loans are annualised. Real deductions are worked out per pay period and rounded down each time, so a year of real payslips can differ by a few pounds.
When we update
Our full standards are set out in the editorial policy.
Rates are reviewed every 6 April when the new tax year starts, and again whenever a Budget or Scottish Budget changes something before then. Each page carries the date it was last reviewed. If you find a page that is out of date or wrong, tell us and we will correct it.