How to calculate discounts before you buy
A sale label gives you one number, but your decision depends on what you actually pay. The discount calculator helps you check a percentage offer or work backwards from an advertised sale price. Use the same currency for every price you enter.
Check a percentage offer
Suppose an item is marked at 500 and the offer is 20% off. Choose “Discount percentage → sale price”, enter 500 as the original price and 20 as the discount. The saving is 500 × 0.20 = 100, so the sale price is 400. A 20% discount means you pay 80% of the original amount.
For an illustrative Philippine peso example, PHP 500 becomes PHP 400. Choosing PHP changes the display label; the calculator does not convert dollars or any other currency into pesos.
Find the percentage from two prices
If the shelf shows an original price of 800 and a new price of 680, choose “Sale price → discount percentage”. Enter 800 and 680. The saving is 120. Divide 120 by 800 and multiply by 100 to get 15%. The original price is the denominator, because the discount describes a reduction from that starting point.
Compare different offers
| Offer | Saving | Price paid |
|---|---|---|
| 10% off | 50 | 450 |
| 20% off | 100 | 400 |
| 30% off | 150 | 350 |
A larger discount does not always mean a cheaper item. Another seller might start with a lower regular price. Compare the final prices for the same product and include delivery or other charges yourself.
Apply successive discounts in order
“20% off, then an extra 10%” is not 30% off. Starting at 500, the first discount gives 400. The second discount saves 40, giving 360. Total savings are 140, or 28% of the original 500. Run the calculator twice, using the first result as the second original price.
Check the terms of the offer
Minimum spend, limited quantities, excluded products and delivery charges can change the amount due. This tool does not validate a promotion or add checkout charges. It also does not judge whether a seller's original price is realistic. Treat the result as an arithmetic check against the prices you can verify.
The original price must be greater than zero. Discounts from 0% to 100% are accepted; a 100% discount gives a zero item price. Displayed money is rounded to two decimal places, so the retailer's final rounding may differ slightly.