Many couples are unable to benefit from the Marriage Allowance; AND the maximum benefit is only £238 (2018/19). But it’s simple to calculate and to claim.
It is for Married Couples and Civil Partnerships where one is a Basic Rate Taxpayer (taxable income £11,850 – £46,350) and the total income for the spouse is below £11,850 (the Personal Allowance).
In this situation, the person with the lower income can transfer up to £1,185 of their unused Personal Allowance to their spouse which – potentially – will save the higher earning spouse up to £238 in income tax (20% x £1,185).
One can claim online at HMRC and backdate the claim to the start of the current tax year. HMRC will then either issue a higher tax code to the person receiving the Marriage Allowance, or, if that person is self-employed, the Marriage Allowance will be given via their Self-Assessment tax calculation.