If you and your partner earn very different amounts, you’ve probably had the thought: why does HM Revenue & Customs treat us as two totally separate people? One of you might be handing over 40% of everything above a certain threshold while the other barely pays any tax at all. Surely there’s a way to even that out?
This is the idea behind “income splitting” — shifting income from the higher earner to the lower earner so less of it gets taxed at the top rate. Some countries let married couples file one combined tax return and effectively average their income for tax purposes. The UK isn’t one of them. But that doesn’t mean couples here have no options. There are legal, HMRC-sanctioned ways to reduce a household’s overall tax bill by making better use of both partners’ allowances — and a few traps that catch people out when they try to get clever about it.
This article walks through what actually works in the UK, who qualifies, and where the line sits between a legitimate tax-saving move and something HMRC will unwind.
Why the UK doesn’t have formal income splitting
In the UK, tax is almost entirely individual. You are taxed on what you personally earn, own, or receive — not on your household’s combined income. There’s no option to file jointly and pool your income the way some other countries allow.
This matters because it means the tax system doesn’t automatically care whether one partner earns £70,000 and the other earns nothing, or whether they each earn £35,000. The first scenario pushes a chunk of income into the 40% higher rate band. The second keeps everything within the 20% basic rate. Same household income, very different tax bill.
Because there’s no formal mechanism to average this out, any “income splitting” in the UK has to happen through legitimate restructuring — moving the underlying asset or income source, not just declaring someone else’s earnings as your own.
Marriage Allowance: the one official scheme that exists
There is one genuinely official, HMRC-run scheme that does something close to income splitting, and it’s called Marriage Allowance (don’t confuse it with the older, mostly obsolete Married Couple’s Allowance, which only applies if one of you was born before 6 April 1935).
Marriage Allowance lets a lower-earning partner transfer £1,260 of their unused Personal Allowance (the amount you can earn before paying any income tax, currently £12,570) to their spouse or civil partner. The transfer is worth up to £252 a year in tax savings, because it reduces the higher earner’s taxable income by £1,260 — taxed at 20%, that’s £252 back.
To qualify:
- You must be married or in a civil partnership (not just living together).
- The lower earner must have income below the Personal Allowance — so they’re not using it all themselves.
- The higher earner must be a basic rate taxpayer — this stops working once their income pushes them into the 40% higher rate band.
You can apply through gov.uk, and you can backdate a claim up to four tax years if you were eligible and didn’t apply at the time — which can mean a useful lump sum if you’ve never claimed before.
It’s a modest saving, but it’s free money for eligible couples who simply haven’t got round to applying.
The bigger
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