Discount Calculator — Calculate Sale Price and Savings Instantly
You see a sign: "30% off!" You want to know: what do I actually pay? What am I saving?
You could do the math in your head, or you could use our free Discount Calculator and get the answer in one second — no math required.
Whether you're shopping for clothes, comparing prices online, or figuring out whether a Black Friday deal is actually good, this tool does the work for you.
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How to Calculate a Discount (The Math)
Understanding the math helps you spot deals quickly — even without a calculator.
Sale Price Formula:
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Sale Price = Original Price × (1 − Discount % / 100)
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Savings Formula:
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Savings = Original Price × (Discount % / 100)
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Example: A $80 jacket is 25% off.
- Savings = $80 × 0.25 = $20
- Sale Price = $80 − $20 = $60
Or directly: $80 × (1 − 0.25) = $80 × 0.75 = $60
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How to Use the Discount Calculator
Our Discount Calculator handles three common scenarios:
Scenario 1: What's the sale price? Enter the original price and the discount percentage → get the final price and savings amount.
Scenario 2: What percentage off is this? Enter the original price and the sale price → get the discount percentage and savings.
Scenario 3: What was the original price? Enter the sale price and the discount percentage → reverse-calculate what the item originally cost.
This last one is useful when a store shows only the sale price but you want to verify the claimed original price.
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Common Discount Percentages — Quick Reference
Don't want to use the calculator for common discounts? Here's a quick mental math guide:
| Discount | What to Multiply By | Trick | |----------|--------------------|----| | 10% off | × 0.90 | Move decimal left, subtract | | 15% off | × 0.85 | 10% + half of 10% | | 20% off | × 0.80 | Multiply by 4, divide by 5 | | 25% off | × 0.75 | Divide by 4, multiply by 3 | | 30% off | × 0.70 | — | | 50% off | × 0.50 | Divide by 2 | | 75% off | × 0.25 | Divide by 4 |
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Stacked Discounts — Are They as Good as They Sound?
"Extra 10% off the sale price!" Sounds like 40% off total on a 30%-off item, right? Wrong.
Stacked discounts don't add up — they compound:
Example: $100 item, 30% off + extra 10% off
- After 30% off: $100 × 0.70 = $70
- After extra 10% off: $70 × 0.90 = $63
Total savings: $37 (not $40). Total discount: 37% (not 40%).
The formula for stacked discounts:
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Effective Discount = 1 − (1 − D1) × (1 − D2)
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Where D1 and D2 are expressed as decimals.
For 30% + 10%: 1 − (0.70 × 0.90) = 1 − 0.63 = 37%
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How to Spot a Fake Discount
Not every "sale" is a real deal. Retailers use psychological tricks that make discounts look better than they are:
1. Inflated "original" prices Some retailers list artificially high original prices to make the discount look bigger. Check price history on tools like CamelCamelCamel (for Amazon) before buying.
2. Anchoring Placing an expensive item next to a slightly less expensive item makes the second item seem like a bargain — even if it's not.
3. Percentage vs. amount "Save $5" and "Save 20%" can be the same discount. Retailers choose whichever sounds larger based on the item's price.
4. The Rule of 100 Research shows that for items under $100, "20% off" sounds better than "$20 off" even when they're identical. For items over $100, the dollar amount sounds larger. Retailers know this.
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When Discount Math Really Matters
Buying in bulk: Is the "buy 3 get 1 free" deal (25% off per unit) better than a 30% off single-item sale? Use the calculator to compare cost per unit.
Coupon stacking: Some stores allow multiple coupons. Calculate each layer separately.
Tax on discounted items: In many regions, sales tax applies to the discounted price. In others, it's calculated on the original price. Know your local rules.
Trade-in discounts: "$200 off when you trade in your old device" — calculate whether the trade-in value is fair compared to selling it yourself.
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Frequently Asked Questions
Q: How do I calculate 20% off a price? A: Multiply the original price by 0.80 (which is 1 − 0.20). For example, 20% off $75 = $75 × 0.80 = $60. Or use our Discount Calculator to skip the math.
Q: What's the difference between a discount and a markdown? A: They're often used interchangeably, but technically a discount is a temporary reduction (like a sale), while a markdown is a permanent price reduction. Both reduce the price you pay — the difference is whether the "original" price will return.
Q: If something is 50% off and then another 50% off, is it free? A: No. The first 50% off brings a $100 item to $50. The second 50% off brings it to $25. You'd need infinitely many 50% discounts to reach zero — but you'd never quite get there (mathematically).
Q: How do I calculate the original price if I only know the sale price and discount? A: Divide the sale price by (1 − discount percentage). Example: if a sale price is $60 after 25% off, the original price = $60 ÷ 0.75 = $80. Our calculator handles this automatically in "Find Original Price" mode.