Rachel earns 60,000 pounds a year in England. On the 2025/26 rates that means 11,432 pounds of income tax and 3,211 pounds of National Insurance. Her personal allowance is 12,570 pounds, the basic rate runs to 50,270 pounds, and every pound above that is taxed at 40 percent.
The useful part was seeing which pounds cost the most. Only the top slice of her pay, the 9,730 pounds above 50,270 pounds, was taxed at 40 percent. That slice cost her 3,892 pounds in income tax on its own.
She asked her employer to put her next 5,000 pound rise into her workplace pension by salary sacrifice instead of into her pay packet. Income tax on that slice went from 2,000 pounds to nothing, National Insurance went from 100 pounds to nothing, and her employer passed on part of its own saving as an extra contribution.
Her take home pay barely moved, because the rise never reached her bank account. Her pension pot grew by more than the rise was worth after tax, and her tax bill fell by roughly 2,100 pounds for the year.
What made it work was order. She checked the pension annual allowance first, confirmed the salary sacrifice arrangement in writing, and kept the payslips showing the reduced gross pay. Nothing here is clever or hidden. It is simply choosing which pot the money lands in before it is taxed.
The lesson: look at the top slice of your income, not the average. That is where the expensive tax lives, and that is the slice worth redirecting.