How to calculate a discount percentage off
The one-line formula that turns any sticker price into the real total.
Smart shopping · no more guessing
Know what you'll really pay
Five quick ways to price a deal — single or stacked discounts, buy-one-get-one, and spend thresholds. Do the math before you hit checkout.
—
Final price
—You save
—Effective discount
—Original total
How it adds up
Calculations assume the store applies each discount once. Some offers cap savings or exclude items — check the small print.
Don't be fooled by rounding
Two discounts are not 30%
Stacked discounts apply in sequence. "20% + 10% off" actually slices 20% first, then 10% of what's left — about 28% combined. Knowing that keeps a "can't-miss deal" honest at the till.
- Pick the offer type that matches the sign in the window.
- Enter the sticker price and any promo maths.
- Read the real total and the effective discount.
- Compare single vs stacked to spend the least.
Discount questions
How do I turn a discount into a price?
Multiply the original price by the discount (as a decimal) and subtract. A $80 item at 25% off is $80 × 0.25 = $20 off — you pay $60.
Why isn't 20% + 10% off equal to 30% off?
Because the second discount applies to the reduced price, not the original. $100 → 20% off → $80 → 10% off → $72. That's a 28% saving, not 30%.
How does Buy One Get One free change the unit price?
You pay full price for one and get another free — two items for the price of one, so each effectively costs half. Buying two gets a true 50% unit saving.
What's a spend-discount deal worth?
If a store takes $20 off every $100, that's a 20% saving only at exactly the threshold. Spend $180 and the saving is about 11% — the rate changes with your total.