Work out the price after a discount — including stacked discounts calculated correctly, where 20% off followed by 10% off is 28% off in total, never the 30% it looks like. Runs entirely in your browser — your numbers never leave this device.
| Step | Price |
|---|---|
| Original price | $100.00 |
| After 1st discount (20%) | $80.00 |
| After 2nd discount (10%) | $72.00 |
Stacked discounts multiply, they don't add: 20% off then 10% off takes 10% off the already-reduced price, so the pair is worth 28% in total — not 30%.
A single discount is one multiplication: 25% off means you pay 75% of the price, so multiply by 0.75. The calculator shows the amount saved as well as the price payable, because the saving is the figure adverts quote and the payable figure is the one that matters at the till. An optional tax step can be applied after the discount, matching how most shops and tax rules actually sequence it: discount first, tax on the reduced price.
Stacked discounts are where intuition fails and this calculator earns its place. A further 10% off an already-reduced price takes 10% of the reduced price, not of the original, so '20% off, then an extra 10% off' removes 28% in total — not 30%. The correct method is to multiply the complements: pay 80% of the price, then pay 90% of that result, which is 72% of the original. The order of the two discounts does not change the final price, since multiplication commutes — 10% then 20% lands on the same 72%.
The reverse question is handled too: given a sale price and an original price, the discount percentage is the saving divided by the original price. That is the check to run when a advertised percentage looks generous — the arithmetic either matches the tag or it does not.
Because the second percentage acts on a smaller base. After 20% off, a $100 item costs $80; 10% off that removes $8, leaving $72 — a total reduction of $28, i.e. 28%. Percentages of changing amounts never simply add. The same trap appears in reverse with price rises and falls: a 30% rise followed by a 30% fall does not return to the start.
No. Multiplying by 0.80 then 0.90 gives the same result as multiplying by 0.90 then 0.80 — both give 0.72 of the original price. What matters is that each discount applies to the running price, not to the original. A shop can advertise the sequence in either order honestly; it cannot honestly add the percentages.
In most retail practice, after: the discount reduces the taxable price, and tax is charged on what you actually pay. The third example shows the sequence — $80 reduced to $60, then 8% tax on $60 gives $64.80. Local rules vary, so if a receipt shows a different sequence, the receipt's method governs; this calculator follows the common one and states it.
Divide the saving by the original price and multiply by 100. An item marked down from $80 to $60 has a saving of $20, and 20 / 80 × 100 = 25% off. Always divide by the original price — dividing by the sale price is the classic error and inflates the apparent discount (20 / 60 would suggest 33.33%).
That the largest discount anywhere in the promotion is 70%, applied possibly to a single item, with everything else discounted less. The phrase is about the maximum, not the typical, item. This calculator deals in the discount on the specific item in front of you, which is the only figure relevant to what you pay.
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