Core comparison
For each job we estimate annual take-home cash after Income Tax, employee National Insurance, student or postgraduate loan deductions and the employee pension contribution. We then add employer pension and the annual value entered for taxable benefits in kind, and subtract commuting, office and travel-time costs. The reverse calculator searches for the new salary that matches the current job's effective annual value.
Income Tax
For 2026/27 the standard Personal Allowance is £12,570 and is tapered above £100,000 of adjusted net income. England, Wales and Northern Ireland use 20%, 40% and 45% main rates. Scotland uses its 2026/27 starter, basic, intermediate, higher, advanced and top bands.
National Insurance
Employee Class 1 National Insurance is estimated using a £12,570 annual primary threshold, an 8% main rate up to the upper earnings limit and 2% above it.
Student and postgraduate loans
The calculator supports one undergraduate plan plus an optional Postgraduate Loan. For 2026/27 the annual thresholds used are £26,900 (Plan 1), £29,385 (Plan 2), £33,795 (Plan 4), £25,000 (Plan 5) and £21,000 (Postgraduate Loan). Undergraduate plans are estimated at 9% above the relevant threshold and postgraduate loans at 6% above their threshold. Real payroll deductions are calculated by pay period, so variable pay can produce a different annual result.
Employee pension deductions
Salary sacrifice reduces the pay used for Income Tax, employee National Insurance and student-loan estimates. A net pay arrangement reduces taxable pay but not the NI or student-loan pay used here. An after-tax or relief-at-source contribution is treated as a cash deduction after PAYE. Pension schemes can use different definitions of pensionable pay, so check your scheme if precision matters.
Benefits in kind
The amount entered is treated as both a non-cash part of the package and taxable employment income for Income Tax. Employee National Insurance is not normally charged on non-cash benefits in kind. Some benefits have special valuation rules, so use the taxable value supplied by your employer where possible.
Commute and time
Annual direct commute cost equals cost per office day multiplied by office days per week and the working-pattern weeks you choose. Travel time is both directions. The personal time value is deliberately user-controlled; set it to £0 for a cash-only comparison.
Official sources
- GOV.UK: Income Tax rates and allowances
- GOV.UK: National Insurance rates and allowances
- GOV.UK: Student and postgraduate loan repayment guidance
- GOV.UK: Tax on company benefits