Where our numbers come from
Sources for every figure
Every rate, band, threshold and allowance on My Salary Calculator comes from the government’s own pages. Here they all are, country by country, with the page each one comes from and the date we checked it.
United Kingdom
Tax year 2026/27
6 April 2026 to 5 April 2027. Checked 6 October 2026.
Tax year 2025/26
6 April 2025 to 5 April 2026. Checked 6 October 2026.
The rules the calculator follows
- The number in a tax code, times ten, is the tax-free amount. BR, D0 and D1 tax all pay at one rate; NT means no tax; 0T means no allowance. Source .
- S at the start of a code means Scottish rates; C means Welsh rates. W1, M1 and X mark an emergency code. Source .
- Welsh rates of income tax are the same as in England and Northern Ireland for both years. Source .
- K codes add to taxable pay, and tax in a pay period can never be more than half of the pay. Source .
- With two undergraduate loan plans you repay 9% once, over the lower threshold; a Postgraduate Loan adds 6%. Source .
- Student loan repayments are worked out on each payday, on the same pay as National Insurance, rounded down to the pound. Source .
- Relief at source adds 20%; higher-rate payers claim more through Self Assessment (in Scotland, 1% at 21%, 22% at 42%, 25% at 45%, 28% at 48%). Source .
- Salary sacrifice lowers the pay that tax and both sides of National Insurance are worked out on. Source .
- No employee National Insurance after State Pension age; employer National Insurance is still due. Source .
- The Personal Allowance taper uses adjusted net income, which is lowered by pension contributions and Gift Aid. Source .
Checked against official worked examples
| Example | Published answer | Published by |
|---|---|---|
| Income tax on £30,000 a year | £3,486 | What is a Tax-Free Personal Allowance? (HMRC Tax Confident) |
| Employee NI on £1,000 in one week | £58 at 8% plus £0.66 at 2% | National Insurance rates and categories (GOV.UK) |
| Employer NI on £500 a week | £60.60 a week | PAYE & National Insurance for Employers (HMRC Tax Confident) |
| Plan 1 student loan on £565 in one week | £4 | Student and Postgraduate Loan deduction tables 2026 to 2027 (GOV.UK) |
| Plan 1 and Plan 2 student loans on £3,200 a month | £86 a month | Repaying your student loan: how much you repay (GOV.UK) |
| Postgraduate Loan and Plan 2 on £2,500 a month | £45 plus £4 | Repaying your student loan: how much you repay (GOV.UK) |
| Scotland against the rest of the UK, 2026/27 | Scotland charges less below £33,500 | Scottish Income Tax 2026 to 2027: technical factsheet (gov.scot) |
| Personal Allowance at £125,140 | £0 | Income Tax: income over £100,000 (GOV.UK) |
| Tax-free pay on code 1257L, paid monthly | up to £1,047 a month | What is PAYE and How is it Calculated? (HMRC Tax Confident) |
What the calculator assumes
- One job, paid through PAYE, in National Insurance category A (or over State Pension age).
- Steady pay through the year, paid monthly, with any bonus paid in one month.
- No benefits in kind, no other income, and no Marriage Allowance unless your tax code includes it.
- Pension percentages are worked out on salary, not on the bonus.
The full method, with the formulas, is on how we calculate.
About our sources
Where do your tax figures come from?
Only from each government’s own published pages. For the United Kingdom that means GOV.UK and, for Scottish rates, gov.scot. We never take a figure from another calculator or a news site.
How often do you check them?
Whenever a budget or a new tax year changes them, and before every tax year starts. The date of the last check is on every page with figures.
I think a figure is wrong. What should I do?
Please tell us at hello@mysalarycalculator.app with the page and the official source you are comparing with. We fix confirmed errors quickly.
Do you check your sums against official examples?
Yes. Our tests compare each calculator with worked examples the government publishes. They are listed under each country below.
Is there an official calculator?
Most governments have one, and each country below links to it. Use it, or your tax authority, for your own tax position.