A discount percentage only becomes useful when you can connect it to the price you will actually pay. Start with the original price, calculate the discounted amount, and subtract it from the original. For one discount, that is all you need. The mistake usually appears when another discount or a tax amount is added.
The basic two-step method
- Discount amount = original price × discount rate.
- Sale price = original price − discount amount.
For a €180 item at 35% off, the discount is €180 × 0.35 = €63. The sale price is €180 − €63 = €117. You can express the same shortcut as €180 × 0.65 because a 35% discount leaves 65% to pay.
Why sequential discounts are not added
Suppose the €180 item is 35% off and there is an extra 10% off at checkout. The second discount is not applied to €180. It is applied to the already discounted €117. The final price is €117 × 0.90 = €105.30. The total saving is €74.70, or 41.5%—not 45%.
| Step | Calculation | Amount |
|---|---|---|
| Original | — | €180.00 |
| After 35% off | €180 × 0.65 | €117.00 |
| After extra 10% off | €117 × 0.90 | €105.30 |
| Total saving | €180 − €105.30 | €74.70 (41.5%) |
Where tax fits
Tax rules and displayed prices vary by location and seller. If a tax rate is added after a discount, multiply the discounted price by one plus the tax rate. Do not assume this order applies everywhere—check the seller’s checkout display and applicable local rules.
A comparison checklist
- Is the advertised “original” price a meaningful comparison price?
- Does a second discount apply to the original amount or the reduced amount?
- Are shipping, tax, membership requirements, or minimum-spend conditions added later?
- Is the same item available elsewhere at a lower final price?
Use the discount calculator to test both discounts and an optional tax rate with your own numbers.
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