The short answer (£45k → £55k)
Moving from £45,000 to £55,000 gross (England/Wales/NI, 2025/26, no pension or student loan) adds about £545/month take-home — not the £833 you might expect from dividing £10k by 12.
At £45,000
£2,993/mo
At £55,000
£3,538/mo
That’s roughly 65% of the raise landing in your pocket. The rest? HMRC’s plus-one at the wedding.
Why raises feel smaller than advertised
- Marginal tax — extra salary is taxed at your top band, not your average rate
- NI — still applies on the uplift (8% in the main band, 2% above £50,270)
- Crossing £50,270 — part of your raise hits 40% Income Tax instead of 20%
- Student loan / pension — can trim the celebration further
Job offer maths
Always compare take-home, not gross. A £5k higher offer might only be £160–£250/month after tax depending on where you sit in the bands. TaxBite shows the bite before you sign.
Compare £45k vs your offer →£55k take-home page → · Bonus tax →
Estimates only — tax codes and benefits change real payslips.