Bonus season: where the smart money actually goes
A UK bonus lands and most of it evaporates into tax. The interesting question is what the remaining chunk does over the next twenty years.
By Mike Gallagher,
The bonus lands. You have about a week before it stops feeling like a windfall and starts feeling like the account balance. That week is where most of the long-term difference happens.
Where the tax goes before you see it
A UK bonus is taxed at your marginal rate. For a higher rate earner, about 42p in the pound is gone to tax and national insurance before the net arrives in the account. If the bonus pushes part of your annual income past £100,000, the effective rate on that slice jumps to 62 percent. If it pushes past £125,140, that slice goes back to 47 percent plus NI.
The net on a bonus is smaller than people expect, often with a chunk having been taxed at the 60p rate. That is not a rounding error. That is a real hit that can be softened at payroll.
The three realistic homes for what's left
- Short-term spending. A meaningful thing. A holiday. Renovations. Some part of the bonus almost always goes here. That is fine.
- ISA or pension contributions. The bit of the bonus that funds your future.
- Paying down debt at a rate you can't beat in the market. Credit card, high-rate personal loans, not usually the mortgage.
Most people don't do badly with the first one. They do badly with the split between the second and the third. The bonus that gets sorted out next month is the bonus that ends up mostly absorbed into lifestyle.
Sacrificing the bonus
Many employers let you sacrifice all or part of your bonus directly into the pension. That is the single highest-return move for a higher rate earner. The gross amount goes in pre-tax, and if you were about to pay 60 percent on part of it, you have saved 60p in the pound plus NI.
Two things to check before you do it.
- Your scheme allows bonus sacrifice. Some do, some don't, some need a form signed before the bonus is declared.
- You are within the pension annual allowance. £60,000 in 2026 for most earners, including employer contributions.
The twenty-year delta
A bonus taken as cash and spent is cash spent. A bonus sacrificed into the pension for a higher rate earner compounds at the pre-tax amount for decades. Over twenty years at 5 percent real return, that grows to several times its original value in today's money. Over twenty-five years it grows to more.
That is not an argument for never enjoying a bonus. It is an argument for knowing what you are choosing. Spending a bonus is a real decision with a real trade-off. Knowing the trade-off makes the decision a better one.
Running the bonus scenario
A Few Quid lets you model a one-off bonus at a specific point in the timeline and see the impact under several allocations. Cash, ISA, pension, mortgage overpayment. The graph shows which one moves the end-state number furthest.
Most bonuses aren't decisions. They're defaults. Turn one default into one deliberate split and the next twenty years look noticeably different.
Then you can enjoy the bit you decided to enjoy without guilt, because the long-term number has been taken care of.