Methodology and assumptions
This site gives annualised estimates. We show the inputs and rules used so you can decide whether a result fits your situation.
What the take-home calculator includes
- Standard Personal Allowance and its taper above £100,000 of adjusted net income.
- rUK Income Tax bands for England, Wales and Northern Ireland.
- Employee Class 1 National Insurance using category A annual thresholds.
- An optional net-pay pension percentage and one student-loan plan.
What it does not model
The current calculator does not model every tax code, benefits in kind, salary sacrifice, multiple employments, variable payroll periods, directors' NI, Scottish Income Tax or relief-at-source pension mechanics. Do not treat it as a payslip or personalised tax advice.
Why monthly results can differ from a payslip
We divide the annual estimate by 12 for a consistent planning view. Payroll software normally calculates deductions by pay period and may use cumulative pay, tax-code changes or rounding. Those differences can change the monthly amount.
Testing and updates
Before a tax-year update is published, calculation changes are checked at the Personal Allowance, National Insurance, higher-rate and Personal Allowance taper thresholds, plus representative pension and student-loan cases. The source list and review date are published on the sources page.