How to Calculate Discounts, Coupons and Final Prices

Check the order of discounts before deciding whether a promotion saves what it claims.

Use the Discount Calculator alongside this illustrative example.

A practical example

An item priced at 100 with a 20% reduction costs 80. A further 10% coupon takes 8 off that reduced price, leaving 72: an overall 28% saving. If an illustrative 5% sales tax is then applied, the total is 75.60. Adding the two discount percentages would produce the wrong answer.

Check the result

Read whether a coupon applies to the item, the basket or only eligible products. Compare the final amount with shipping and any excluded charges recorded separately.

Try a comparison

Compare the stacked reduction with a single 30% discount on the same 100 price. The single discount gives 70 before tax, while the 20% plus 10% stack gives 72. The difference explains why an advertised sum of percentages can mislead.

What this does not establish

The tax percentage is an input, not a location-aware tax determination. A retailer may apply a different legally required calculation order.

Report unclear guidance or a result that needs checking.