If a sale price is stated after a discount, it represents the percentage left to pay. A 20% discount leaves 80%, or 0.80, of the original price.
Worked example
For a sale price of €72 after 20% off: €72 ÷ 0.80 = €90. The implied original price is €90. If the discount is 35%, divide by 0.65 because 65% remains.
What the calculation cannot know
It cannot tell whether the claimed original price was the usual market price, whether the product was available elsewhere for less, or whether shipping, tax, membership conditions, or extra discounts apply.
Use the final checkout amount
Compare the amount you would actually pay, including relevant delivery and tax. Use the original-price calculator together with the sequential discount tool on the homepage.
Use the related calculator, then read our methodology, sources, and editorial policy. Spot an error? Contact the site.