How to use the Percent Off Calculator
- Enter the original ticket price.
- Enter the advertised percentage off.
- Read the price you pay and the amount you save.
- For a second discount, re-enter the new price and apply the next percentage.
How the calculation works
A discount multiplies the price by (1 − rate). A 30% reduction leaves 70% of the ticket price, so 89.99 × 0.70 = 62.99. Working with the remaining fraction rather than subtracting the saving is faster and less error-prone, especially mentally.
Stacked discounts multiply, they do not add. An extra 20% off an already 30%-off item leaves 0.70 × 0.80 = 0.56 of the original — a 44% total reduction, not 50%. Order does not matter for percentage discounts, but it does matter when a fixed-value coupon is involved: applying the fixed amount before the percentage almost always leaves you paying more, which is why terms usually specify the sequence.
Sales tax is applied after the discount in most jurisdictions, so calculate the reduced price first and add tax to that figure.
Sale price = price × (1 − percent/100) ; stacked = price × (1 − r₁) × (1 − r₂)Source: Standard retail discount arithmetic; sequential-discount conventions in consumer pricing.
Worked example
A £150 jacket at 40% off, with an extra 15% member discount at the till.
- First discount: 150 × 0.60 = £90.
- Member discount: 90 × 0.85 = £76.50.
- Total saved: 150 − 76.50 = £73.50.
£76.50 to pay — a 49% total reduction, not the 55% the two labels might suggest.
Frequently asked questions
Do two discounts add together?+
No. They multiply, so 30% plus 20% is a 44% total reduction.
Is tax calculated before or after the discount?+
After, in most places — tax applies to the amount actually paid.
How do I find the original price from a sale price?+
Divide the sale price by (1 − rate). £70 after 30% off implies an original of £100.
What about buy-one-get-one-free?+
That is a 50% discount only if you want both items; on a per-item basis it is 50%, on a needed-item basis it is 0%.
Last reviewed September 1, 2026. We review this page whenever the underlying formula, tax year, published rate or standard changes.