Change calculator

How the calculation works

Change is the difference between what the customer handed over and the purchase total:

change = amount paid − purchase total

A positive result is the change to return. Zero means exact payment. A negative result means the customer still owes that much.

Purchase of R$37.50, customer pays with R$50:

50.00 − 37.50 = R$12.50 change.

To use the fewest bills, go from largest to smallest. R$12.50 = one R$10 note + one R$2 + one R$0.50 coin.

Add everything the customer gave into "amount paid".

What if paying with multiple notes?

Add it all up in "amount paid". A R$20 note plus R$15 in coins is R$35 paid.

How to give change with fewer coins?

Start with the largest bills and coins and work down until the change is complete. That uses the fewest pieces.

The change came out negative, what now?

It means the amount paid was less than the purchase — the customer still owes that difference.

How do I give change with the fewest bills?

Always go from the largest denomination down: take the biggest note that fits, subtract, and repeat with the remainder.

Can a shop round up when it has no coins?

Consumers are entitled to correct change. Rounding in the customer's favour is common, but charging more to square the amount is not allowed.

What is the quickest way to check change?

Count up instead of subtracting. On a R$37.40 purchase paid with R$50: 60 cents to R$38, R$2 to R$40, R$10 to R$50 — change of R$12.60.