Discount Calculator
CalculatorsFind a sale price from an original price and discount percentage, or work out what percentage discount a sale price represents — computed locally in your browser.
Sale price
$80.00
You save
$20.00
Discount
20.0%
Two directions of the same calculation
This calculator works both ways. "Find sale price" mode takes an original price and a discount percentage and tells you the final price and how much you save — useful when you see a "25% off" sign and want to know the actual dollar amount before checking out. "Find discount %" mode takes an original price and a sale price you've already seen and works out what percentage discount that actually represents — useful for comparing two differently-worded deals ("$20 off" vs. "15% off") on an apples-to-apples basis.
The formula behind it
The core relationship is straightforward: sale price = original price × (1 − discount ÷ 100). So a $80 item at 25% off becomes $80 × 0.75 = $60. Working backward from a sale price to a discount percentage rearranges the same formula: discount % = (original price − sale price) ÷ original price × 100.
Watch out for stacked discounts
A common shopping mistake is assuming two discounts add up directly — "30% off, plus an extra 20% off" is not a 50% total discount. Stacked percentage discounts apply sequentially, each to the already-discounted price, so the real combined discount is smaller than the sum: a $100 item at 30% off becomes $70, and a further 20% off that $70 brings it to $56 — a 44% total discount, not 50%. This gap grows with larger individual discounts, so it's worth calculating stacked discounts step by step rather than adding the percentages together.
Comparing dollar-off vs. percent-off deals
A flat dollar amount off ("$15 off") and a percentage off ("20% off") aren't directly comparable without knowing the original price, since a percentage's dollar value scales with the price while a flat discount doesn't. On a $50 item, 20% off ($10) beats $15 off... actually the reverse — on a $50 item, $15 off beats 20% off ($10), but on a $150 item, 20% off ($30) beats a flat $15 off. Running both numbers through a calculator before assuming which deal is better avoids a surprisingly common miscalculation, especially since retailers tend to advertise whichever framing (dollar or percent) makes a given deal sound most impressive.
How to use Discount Calculator
- 1Choose 'Find sale price' or 'Find discount %'.
- 2Enter the original price and either the discount percentage or the sale price.
- 3Read the calculated sale price, amount saved, and discount percentage.
Frequently asked questions
Do two stacked percentage discounts add together?
No — stacked discounts apply sequentially to an already-reduced price, so the combined discount is smaller than simply adding the two percentages together.
How do I compare a dollar-off deal to a percent-off deal?
Convert both to a final price using the original price — a percentage discount's dollar value scales with price, so which deal is better depends on the item's price, not just the advertised numbers.
What's the formula for a sale price?
Sale price = original price × (1 − discount % ÷ 100).
Can I find the discount percentage if I only know the sale price?
Yes — switch to 'Find discount %' mode and enter both the original and sale price to calculate the percentage.
Is my pricing information stored anywhere?
No — the calculation runs entirely in your browser and isn't sent to a server.