Reverse tax calculator
Rent, bills and the life you want are all monthly take-home numbers, but job adverts and salary negotiations speak in gross. This calculator works backwards: tell it the net you need, it finds the salary that delivers it, to the penny, for 2026/27.
To take home £30,000 a year (£2,500.00 a month) you need a salary of
£36,778
That salary pays £4,841.67 income tax and £1,936.67 National Insurance, you keep 81.6%.
How the reverse calculation works
There is no formula that runs the tax system backwards, because the marginal rate changes at every band edge. The engine finds your answer by bisection: it searches for the gross salary whose forward calculation lands on your target net to the penny, using exactly the same maths as the main calculator. The test suite verifies the round trip, net to gross to net, returns the number it started with.
Assumes the standard 1257L tax code, no pension and no student loan, each of those raises the salary you'd need.
Why the required salary grows faster than the target
Each extra pound of take-home costs more gross than the last, because the extra gross is taxed at your marginal rate. Going from £2,000 to £2,500 a month of net needs £8,333 more salary; from £5,000 to £5,500 needs £10,345; and inside the £100k taper, from £6,500 to £7,000 costs £11,403 of gross, every figure here computed by the engine, not estimated. Negotiate in gross, but sanity-check in net.
Related tools
- Take-home pay calculator: the forward direction, with pension and student loans.
- Hourly wage calculator: the same conversion for hourly rates.
- Pro rata calculator: part-time equivalents of a full-time salary.
2026/27 rates, checked 2026-08-28. Method on the about page.