When you get married during a tax year or enter into a civil partnership you may be entitled to a tax refund. This will depend on the amount of income of each of the couple and the time of year involved.
Two calculations are required. The first involves calculating your tax as though you were two single people for the whole of the tax year.
The second calculates your tax as though you were a married couple/ civil partnership for the whole of the tax year.
If the second calculation gives a lower tax bill the difference between the two claculations is called a refund. This refund is then time apportioned over the tax year. for example if you got married half way during the tax year you would be entitled to 50% of this refund. If you got married at the end of the tax year no refund would be due.
Refunds will only arise where one of the couple pays tax at the low rate (20%) and the other at the top rate (40%). If both parties pay tax at the same rate as single persons then no refund will be due.