If you pay Income Tax at the basic rate no additional relief is due on your charitable donations. However, if you are a higher rate or additional rate taxpayer then you can claim tax relief on the difference between the basic rate and your highest rate of tax. This relief is given by increasing your basic rate and higher rate band by the grossed-up amount of your gifts.
If you are a higher rate or additional rate taxpayer you have the option to carry back your charitable donations to the previous tax year. A request to carry back the donation must be made before or at the same time as your previous year’s self-assessment return is completed.
This means that if you made a gift to charity in the current 2020-21 tax year that ends on 5 April 2021, you can accelerate repayment of any tax associated with your charitable giving. This can be a useful strategy to maximise tax relief if you will not pay higher rate tax in the current tax year but did in the previous tax year.
You can only claim if your donations qualify for gift aid. This means that your donations from both tax years together must not be more than 4 times what you paid in tax in the previous year. If you do not complete a tax return you can submit a claim using HMRC’s P810 form.