The UK system differs from the US one, which causes a lot of confusion:
- Basic-rate taxpayers — you claim nothing. The charity reclaims 25p per £1 through Gift Aid.
- Higher-rate (40%) — reclaim roughly £25 on a £100 Gift Aided donation via Self Assessment or a tax-code adjustment.
- Additional-rate (45%) — reclaim roughly £31 on the same £100.
Payroll Giving is the exception that behaves more like a deduction: the gift leaves gross pay before Income Tax, so relief is immediate at your top rate.
Gifts of shares, securities or land are more generous still — no Capital Gains Tax on the disposal and market value deductible against Income Tax.
This is general information, not tax advice — see tax-efficient giving.