How HMRC calculates the Gift Aid total
This support article explains how HMRC calculates the Gift Aid total for Gift Aid claims, and covers why there may sometimes appear to be discrepancies, based on rounding.
In this article:
The two ways of calculating Gift Aid per donor
When you create a Gift Aid claim, each of the donations within the claim is shown. To the right of the 'Donated amount' column, there is also a 'Gift Aid amount' column, which shows the amount of Gift Aid relating to each donation.
While this is a useful way to view the data, HMRC requires Gift Aid claim data to be aggregated by donor. This means that where a donor gives multiple donations, instead of each donation being submitted as a separate line, these lines are aggregated together, and it's the total that is submitted to HMRC.
As a result, there can be a slight difference in the Gift Aid amounts, depending on whether they're calculated as an aggregated total, or as a sum total of the Gift Aid amounts column. This difference is illustrated by the example below.
An example
In this example, there are 3 donations given by a donor, totalling £22.50. They appear to have a Gift Aid amount of £5.64.
| Donation Amount | Gift Aid Amount | |
| Dan Jones Donation 1 | £7.50 | £1.88 (25% of £7.50, rounded to the nearest penny) |
| Dan Jones Donation 2 | £7.50 | £1.88 (25% of £7.50, rounded to the nearest penny) |
| Dan Jones Donation 3 | £7.50 | £1.88 (25% of £7.50, rounded to the nearest penny) |
| Total | £22.50 | £5.64 (sum of the Gift Aid amounts above) |
However, this isn't how HMRC calculates the Gift Aid amount. Instead, they sum the total donations given by the donor in the claim, and calculate Gift Aid from this total.
| Donation Amount | Gift Aid Amount | |
| Dan Jones Total Donations | £22.50 | £5.63 (25% of £22.50 rounded to the nearest penny) |
In this example, it would appear that HMRC had underpaid Gift Aid by 1p (and with other examples, this could equally be an apparent overpayment of a few pence).
The difference arises because you get a different total depending on how the calculation is done, and whether you:
- calculate the Gift Aid on each donation, then add these together, or
- total each donor's donations, then calculate Gift Aid on that donor's total.
As HMRC's method uses option 2, it's worth bearing in mind that if your calculations are based on option 1, then you may well get a different answer (typically, by a few pence).