The Discount Calculator takes a list price, one or two discount percentages and (optionally) a sales-tax rate, and returns the final sale price, the amount you save and the effective discount. It's the fastest way to check whether that "50% off + extra 20%" sign at the mall is actually a good deal.
The formulas
- Sale price = List × (1 − d/100)
- Amount saved = List × d/100
- Stacked discount = List × (1 − d₁/100) × (1 − d₂/100)
- With tax = Sale × (1 + t/100)
Worked examples
Single discount
A 120 jacket at 25% off. Save 30. Sale price = 90.
Stacked discount
Same 120 jacket, 25% off then an extra 20% at checkout. Sale price = 120 × 0.75 × 0.80 = 72. Effective discount = 40% (not 45%).
With sales tax
72 sale × 1.08 (8% tax) = 77.76 out the door.
Where discounts show up
- Retail sales, Black Friday, Cyber Monday and end-of-season clearances.
- Coupons, loyalty rewards and cashback offers.
- Bulk buys and volume-based B2B pricing tiers.
- Prompt-payment discounts on invoices.
Tips and common traps
- Retailers often mark prices up before "discounting" them. Check price history.
- Two 25%-off stacked is 43.75%, not 50%.
- Free shipping is worth 8–15% on small orders — factor it in.
Frequently asked questions
How is a discount calculated?+
Sale price = list price × (1 − discount%/100). The amount saved is list price × discount%/100.
How do I apply two discounts together?+
You can't just add them. 20% off, then an extra 10% off = 0.80 × 0.90 = 0.72, i.e. 28% off — not 30%. Use the stacked-discount example below.
Does the calculator include tax?+
Yes. Add your local sales tax / VAT / GST rate and the final price will include it after the discount is applied.
What is the effective discount if I get an extra amount off?+
Effective % = amount saved ÷ original price × 100. Buying a 500 jacket for 325 is a 35% effective discount.
Is buy-one-get-one-free a 50% discount?+
Only if you were going to buy two anyway. For a single item it's still full price.