What is your donation actually worth?

When a UK taxpayer donates to a UK-registered charity and ticks the Gift Aid box, the charity claims back the basic-rate tax (20%) that you would have paid on the underlying income. The maths is from the GROSS donation, so a £100 net donation has a gross value of £125 to the charity (£100 ÷ 0.80).

You don't need to do anything for the charity to claim the basic-rate uplift, beyond ticking the box and confirming you've paid enough income or capital gains tax in the year to cover the claim. If you haven't paid enough tax to cover it, HMRC can ask you for the difference, so don't Gift Aid donations made when you weren't a taxpayer.

The charity only ever claims the basic rate. If you pay 40% or 45%, you can reclaim the rest yourself through Self Assessment. The relief is the difference between your marginal rate and 20%, applied to the GROSS donation. For a higher-rate taxpayer that's 20% of £125 = £25 back on every £100 net donation.

You can carry a donation back one tax year on your Self Assessment if it's more useful in the previous year. Useful if you've dropped down a band or if you've already filed and want to apply this year's donations to last year's bill.

Scotland sets its own income tax bands, but Gift Aid is reserved to Westminster and still claims back the UK basic rate (20%). If you pay the Scottish intermediate rate (21%), you can reclaim 1%. At the Scottish higher rate (42%) you reclaim 22%. The advanced (45%) and top (48%) rates work the same way: the charity gets the same £125 from a £100 net donation, and you reclaim the gap between your Scottish rate and the UK basic rate.

An alternative scheme: your employer takes the donation out of your salary BEFORE tax. The charity receives exactly what you donate (no Gift Aid uplift), and the tax saving is immediate through your payslip rather than a year-end reclaim. For higher and additional-rate taxpayers, Gift Aid + Self Assessment slightly out-performs Payroll Giving on £ to charity per £ spent, but only if you actually file the reclaim. If you don't file Self Assessment, or you'd rather have the tax saving instantly, Payroll Giving is the better choice.

Donations of shares, land or buildings get different (more generous) tax treatment. Legacies in wills are exempt from inheritance tax and can reduce the IHT rate on the rest of the estate. CAF accounts and donor-advised funds let you Gift Aid in once and then donate to multiple charities over time. The calculator above is for the most common case: a cash donation by a UK taxpayer to a registered charity.

For binding tax advice, especially on larger donations, talk to an accountant. We're working from public HMRC rules (gov.uk/donating-to-charity); the calculation is straightforward but your individual position may not be.