How we handle tax rounding

Tax is worked out per line and then rounded to the nearest cent. A shop that rounds each line and a shop that rounds the total once will print slightly different figures for the same basket. Neither is wrong.

On a receipt with 40 items, those individual roundings can add up to twenty cents. That is normal arithmetic, not a mistake by the shop or by us.

We allow half a cent per taxed line, rounded up, and never less than one cent. A receipt with one taxed line may differ by a cent. A receipt with 40 taxed lines may differ by twenty.

Within that, we call the receipt balanced. Beyond it, we say the tax difference is unresolved and show you the amount and the direction, because a difference that large is usually telling you something.

When a difference is within tolerance, we record it as an explicit rounding adjustment against one tax band, chosen by a fixed rule so the same receipt always gives the same answer.

We never quietly change the tax on a band to make the sums come out. The band keeps the figure it earned and the adjustment sits beside it, so if your accountant asks why a band is a cent off, there is an answer on the screen instead of silence.

If you do want to settle it

There are three ways, and we ask which one because they mean different things and we record the reason against your name:

• Round it into a band. The lines are right and the difference is rounding. Nothing about what you bought changes.
• Use the line totals. The lines are right and the printed tax total is not. The amount you actually paid does not change.
• Enter the correct figure. We misread the receipt. You tell us what it really says.

Whichever you choose is recorded with your name, the date and both figures, so the change can be explained later.