Discount Calculator — How to Calculate Sale Price
Find the final price from an original amount and percent off. Example: 100 off 20% → 80. Optional second discount stacks on the reduced price. Browser-only math for shopping and homework — not a store checkout.
How it works
Enter the original price and the percent off. Optionally add a second percent that stacks on the reduced amount. The page shows the final price and how much you save. Runs in your browser.
Formula
Final = original × (1 − d₁/100) × (1 − d₂/100) when a second discount is set; otherwise omit the second factor. Notes:
- d₁ and d₂ are percent-off values (20 means 20% off), not multipliers like 0.8.
- Leave the second discount empty or 0 to apply a single markdown.
- Taxes, coupons with fixed amounts, and store rounding rules are not modeled.
Example
Example: original 100, 20% off → final = 100 × 0.8 = 80 (saved 20). With a second 10% off → 80 × 0.9 = 72.
When to use it
- Compare a single sale percent to the checkout total before tax.
- Homework: practice successive percent-off discounts.
- Rough double-discount stacks for marketing math drills.
Frequently asked questions
How is a double discount applied?
The second percent multiplies the already discounted price, not the original.
Is 20% off the same as paying 20%?
No. 20% off means you pay 80% of the original (multiply by 0.8).
Does this include sales tax?
No. Enter pre-tax amounts; tax pages are separate.
Can I enter a fixed dollar coupon?
This page uses percent-off only. Subtract a fixed coupon yourself before or after.
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Questions or feedback
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