Marginal deductions
Basic-rate earners lose 28% of a rise (20% tax + 8% NI), plus 9% if repaying a student loan. Higher-rate: 42%. Between £100,000 and £125,140 the effective rate is 62% because of the personal allowance taper.
FAQ
How much of a £2,250 rise on £45,000 do I keep?
About £1,418 with a Plan 2 loan (63%).
Sources (checked 6 Nov 2026): HMRC rates 2026/27.