BEHIND THE NUMBERS
How this calculation works
Change = cash received − amount due, in integer pence. For non-negative change, take the largest permitted sterling denomination, then repeat with the remainder. A negative result is a payment shortfall.
Worked example
£20 − £18.37 = £1.63: £1 + 50p + 10p + 2p + 1p.
Example result: £1.63
Count the change back
The breakdown is a suggested way to make the exact amount using the permitted denominations. Check its subtotal against the displayed change before handing over the cash.
A payment can be incomplete
If the customer pays less than the bill, the result identifies the amount still due instead of offering negative coins.
Assumptions and rounding
- The selected denominations are available without quantity limits.
- Amounts must have no more than two decimal places.
Questions about this calculator
Does it use £100 notes?
No. Change is limited to the selected £50-or-smaller note set and standard coins.
Can I use a different mix?
Yes. The suggested mix is not a check of the notes and coins available in your drawer.