Our methodology
Every calculator on YourPayUK is built around official UK pay, tax and statutory payment rules. This page explains where our figures come from, what assumptions we make, and how often we check everything is still correct.
Where our figures come from
Our calculators use rates, thresholds and formulas published by UK government sources, including HMRC and GOV.UK guidance on Income Tax, National Insurance, statutory payments (such as Statutory Sick Pay and Statutory Maternity Pay), and the National Minimum and National Living Wage.
How often we review rates
UK tax and payroll rates typically change at the start of each new tax year on 6 April. We review every calculator against the current tax year’s published rates and update them accordingly. Where a calculator states a specific tax year (for example, “2026/27”), that reflects the figures it was last checked against.
What our calculators do and don’t account for
Our calculators are built to give clear, useful estimates for common situations — not a complete replacement for a payslip, tax return, or professional advice. Depending on the calculator, some things are deliberately simplified or not included, such as:
- Individual tax codes other than the standard Personal Allowance
- Salary sacrifice arrangements, unless a calculator specifically covers this
- Student loan repayments
- Regional variations, such as Scottish Income Tax rates, unless stated
- Company-specific benefits, bonuses, or contractual variations
Where a calculator makes a specific assumption (such as a standard working week or a flat tax code), this is noted directly on that calculator’s page.
Estimates, not guarantees
Every result on this site is an estimate for general guidance. Your actual pay, tax or entitlement may differ based on your individual circumstances. For anything with real financial or legal consequences, we’d always recommend checking with HMRC, ACAS, or a qualified accountant.
Spotted something that looks wrong?
We rely on our calculators being accurate, so if a figure looks off, please let us know via our Contact page — we check and correct issues as quickly as we can.