Free UK salary sacrifice calculators for pensions, bonuses, the £100k tax trap and employer NI savings. All use 2026/27 rates.
Salary sacrifice means giving up part of your gross salary in exchange for a benefit — most often pension contributions — so you pay less income tax and National Insurance on the amount sacrificed. The calculators here model that trade-off for different situations: a general pension sacrifice, an electric-car scheme, cycle-to-work, bonus sacrifice, and the employer's National Insurance saving.
Because sacrifice reduces the pay that tax and NI are charged on, the saving depends on your tax band and the type of benefit. Employees save income tax plus National Insurance on the sacrificed amount, and employers save the 15% employer National Insurance — a saving many choose to add straight into your pension. Start with the calculator that matches your scheme, then compare the take-home and pension outcomes before deciding how much to sacrifice.