Pension on a £125,000 salary — additional rate begins.

£125,140 is the threshold above which additional rate (45%) income tax kicks in. At £125,000 you're sitting just below it, with your personal allowance fully tapered to zero. Your income tax bill is around £40,432. The marginal value of pension contributions across the £100k-£125,140 band is 60% (the personal allowance taper + 40% tax) — so a £25,000 pension contribution from £125k brings you back to £100k effective income and saves you around £15,000 in tax. Above £125,140, additional rate tax means the marginal saving on contributions is 47% (45% tax + 2% NI). Either way, the salary sacrifice or RAS calculation is overwhelming: contributing 20-25% of salary into a pension on £125k is mathematically optimal for most people who don't need every pound of take-home for ongoing living costs.