Yes, it is generally worth claiming the UK Married Couple’s Allowance (MCA) if you or your partner were born before 6 April 1935, as it can reduce your annual tax bill by between £436 and £1,127 for the 2025/26 tax year. It is a tax-efficient, non-refundable deduction based on income, typically reducing the tax due for couples in civil partnerships or marriages.
Marriage allowance could be worth giving a closer look if you are on maternity leave, stay-at-home parents, retired, self-employed and unemployed, and your spouse is not a higher or additional rate taxpayer. To apply for the marriage allowance, go to the government website.
A single filer with no children should claim a maximum of 1 allowance, while a married couple with one source of income should file a joint return with 2 allowances.
The main disadvantages of filing jointly are joint liability (you're responsible for your spouse's tax errors), potential loss of eligibility for certain deductions (like medical expenses when incomes are combined), and being liable for a spouse's back taxes or debts, which can even intercept your refund. Filing jointly can also sometimes push you into a higher tax bracket, even if filing separately would save you money.
Filing jointly typically offers the most tax advantages for married couples, including: Higher Standard Deduction: In 2025, married couples filing jointly get a standard deduction of $31,500, compared to $15,750 for married filing separately.
While the tax code encourages married couples to file their tax returns jointly, there are a few scenarios where married filing separately could be beneficial. These include when both spouses have about the same amount of income and when combining income pushes a couple into a higher tax bracket.
Marriage Allowance is sometimes referred to as the Marriage Tax Allowance. You might qualify for Marriage Allowance if: you're married or in a civil partnership, and don't receive Married Couple's Allowance. you do not pay income tax or you earn less than your Personal Allowance so are not liable to tax.
For married couples filing jointly, claiming 0 allowances (or using the default settings for two incomes on the newer W-4) typically results in more tax withheld, aiming for a smaller refund or no tax due; claiming 1 allowance (or adjusting for two incomes) means less withheld, boosting take-home pay but increasing the chance of owing taxes. The best choice depends on your combined income and whether you prefer a larger paycheck (claim 1/adjust) or a bigger refund (claim 0/adjust more). For the most accuracy, use the IRS Tax Withholding Estimator, especially if incomes are uneven, as the old allowance system is gone on new W-4s.
Getting your federal tax allowances wrong can carry consequences: Too Many Allowances (Under-Withholding): You'll take home more pay during the year but risk owing taxes and possibly penalties when filing. Too Few Allowances (Over-Withholding): More money is withheld, which often results in a larger refund.
For married couples, tax relief often comes from filing jointly, which provides a much larger standard deduction (e.g., $32,200 for 2026) and allows access to more tax credits, but filing separately can sometimes benefit couples with large income differences or significant medical expenses, while also offering relief for injured or innocent spouses. The best strategy depends on your combined income, deductions, and specific situations, with joint filing usually yielding greater overall savings.
Married filing jointly if you're married or if your spouse passed away during the year. Married filing separately if you're married and don't want to file jointly or find that filing separately lowers your tax. Most couples save money by filing jointly.
Marriage Allowance lets you transfer £1,260 of your Personal Allowance to your husband, wife or civil partner. Your Personal Allowance is the amount you can earn before paying tax. This reduces their tax by up to £252 in the tax year (6 April to 5 April the next year). This guide is also available in Welsh (Cymraeg).
You can backdate Marriage Allowance claims by up to 4 years, but you must be eligible for all of those years.
A couple may pay the IRS less by filing separately when both spouses work and earn about the same amount. When they compare the tax due amount under both joint and separate filing statuses, they may discover that combining their earnings puts them into a higher tax bracket.
If you're married, you can claim two allowances – one for you and one for your spouse. * You can divide your total allowances whichever way you prefer, but you can't claim an allowance that your spouse claims too.
If you claimed 0 and still owe taxes, chances are you added “married” to your W4 form. When you claim 0 in allowances, it seems as if you are the only one who earns and that your spouse does not. Then, when both of you earn, and the amount reaches the 25% tax bracket, the amount of tax sent is not enough.
The IRS may disallow your return and recalculate your taxes under the correct status. You could lose credits and deductions claimed under “Single.” You may owe additional tax, interest, or even accuracy-related penalties. In cases of deliberate misfiling, the IRS could pursue fraud charges underIRC § 7206or § 7201.
There are no longer any special state pension arrangements for married couples, meaning each individual in a marriage or civil partnership needs to build up their own state pension. Our guide to how the state pension works provides more information.
If both spouses are on the mortgage, filing jointly (MFJ) may be more beneficial for combined income and deductions. If only one is responsible for the mortgage, it can affect their tax burden if they file separately.
When you are married and file a joint return, your income is combined—which, in turn, may bump one or both of you into a higher tax bracket. Or, one of you is a higher earner, that spouse may find themselves in a lower tax bracket. Depending on your situation, this could be a tax benefit of being married.