Discount Calculator | Free Percent Off & Savings Tool
Quickly calculate sale prices, savings, and discount percentages. Supports stacked discounts, sales tax, quantity pricing, and side-by-side comparison. Free and easy to use.
How Discounts Work
A discount is a reduction from the original price. Discounts come in two main forms: Percentage off (20% off, 50% off) where savings scale with price, and fixed amount off ($10 off, $25 off) where savings are the same regardless of price.
How the Discount Calculator Works
Our discount calculator offers four powerful modes to handle any discount scenario:
Percent Off
Enter the original price and discount percentage to instantly see your savings, final price, and per-item cost. Includes sales tax and quantity options for bulk purchases.
Original Price
Know the sale price but not the original? Enter the sale price and the discount % to reverse-engineer the original price and see your total savings.
Discount Percentage
See a great deal but not sure what % you're saving? Enter the original and sale price to calculate the exact discount rate and your total savings.
Stacked Discounts
Chain up to 3 discounts sequentially (e.g., 20% off + extra 10% off). See the exact step-by-step math and compare the effective rate against a single discount.
The Discount Formula (Step-by-Step)
Step 1: Discount Amount = Original Price × (Discount % ÷ 100). Step 2: Final Price = Original Price - Discount Amount. Shortcut: Final Price = Original Price × (100% - Discount%) ÷ 100. Example: 30% off $80: $80 × 0.70 = $56.
Discount Formulas Explained
Percent Off Formula
Discount Amount = Original Price × (Discount % ÷ 100)
Sale Price = Original Price − Discount Amount
Example: $100 at 20% off = $100 × 0.20 = $20 discount. Sale price = $80.
Stacked Discount Formula
Stacked discounts are applied sequentially, not added together.
Final Price = Original × (1 − D1%) × (1 − D2%) × (1 − D3%)
Example: $100 with 20% + 10% off = $100 × 0.80 × 0.90 = $72 (28% effective, not 30%).
Find Original Price
Original Price = Sale Price ÷ (1 − Discount % ÷ 100)
Example: You paid $80 after a 20% discount → $80 ÷ 0.80 = $100 original price.
Find Discount Percentage
Discount % = ((Original − Sale) ÷ Original) × 100
Example: $100 original, $80 sale → ($20 ÷ $100) × 100 = 20% discount.
Finding the Original Price from a Sale Price
Original Price = Sale Price ÷ (1 - Discount% ÷ 100). Example: A shirt is on sale for $36 with 20% off. Original = $36 ÷ 0.80 = $45. Common mistake: Don't just add 20% to $36 — that gives $43.20, which is wrong.
Stacked Discounts: They Don't Add Up
Stacked discounts are applied sequentially, not cumulatively. $100 item with 20% off + 10% off: $100 × 0.80 = $80, then $80 × 0.90 = $72. Total savings: $28 (28%, not 30%). Formula: multiply remaining percentages — 0.80 × 0.90 = 0.72.
How Sales Tax Affects Your Savings
Discounts are applied before sales tax. A 25% discount on $100 with 8% tax: you save $25 on the price plus $2 on the lower tax. Total savings: $27, not just $25.
Smart Shopping Tips
Check the Effective Rate
50% off + 20% off is not 70% off — it's 60% off! Use our Stacked Discounts mode to see the real effective discount rate.
Compare Before You Buy
Use our side-by-side comparison to see what 15%, 20%, 25%, and higher discounts mean for your wallet — sometimes an extra 5% off makes a big difference.
Include Tax for True Cost
Sales tax can add 5-10% to your final cost. Toggle on the tax option to see what you'll actually pay at checkout — no surprises.
Common Discount Quick Reference
How much you save and pay at common discount rates on a $100 item:
| Discount | You Save | You Pay | Per $100 |
|---|---|---|---|
| 5% off | $5.00 | $95.00 | Save $5 |
| 10% off | $10.00 | $90.00 | Save $10 |
| 15% off | $15.00 | $85.00 | Save $15 |
| 20% off | $20.00 | $80.00 | Save $20 |
| 25% off | $25.00 | $75.00 | Save $25 |
| 33% off | $33.00 | $67.00 | Save $33 |
| 40% off | $40.00 | $60.00 | Save $40 |
| 50% off | $50.00 | $50.00 | Save $50 |
| 60% off | $60.00 | $40.00 | Save $60 |
| 75% off | $75.00 | $25.00 | Save $75 |
Percentage Off vs Fixed Amount: Which Is Better?
Fixed Amount Off
$20 off is better on a $50 item (40% savings). Better for cheaper items.
Percentage Off
25% off is better on a $500 item ($125 savings). Better for expensive items.
Crossover: Fixed Amount ÷ Percentage as decimal. Below that price, fixed is better. Above it, percentage is better.
Real-World Shopping Examples
Black Friday Deal
Laptop at $1,200 with 20% off + extra 10% + $50 rebate: $1,200 × 0.80 = $960, × 0.90 = $864, - $50 = $814. Total savings: $386 (32.2%).
BOGO 50% Off
Two $30 items cost $30 + $15 = $45 — that's 25% off per item on average.
Common Discount Mistakes
Adding Stacked Percentages
20% + 10% = 28%, not 30%. Stacked discounts multiply, not add.
Reversing the Formula
Finding original price requires division, not addition. $36 ÷ 0.80 = $45, not $36 + $7.20.
Ignoring Sales Tax
Your total savings include the lower tax amount. 25% off $100 with 8% tax saves $27, not just $25.
Ignoring Unit Prices
A bigger discount on a more expensive item may cost more.
Falling for Anchor Pricing
"Was $200, now $80!" may not reflect true original price. Check market prices before buying.
Key Takeaways
- Quick formula: Final Price = Original × (1 - Discount/100)
- Find original price: Sale Price ÷ (1 - Discount/100)
- Stacked discounts multiply — 20% + 10% = 28% total, not 30%
- Tax is calculated after discounts — you save on tax too
- Compare final prices, not just percentages, when shopping
Frequently Asked Questions
How do I calculate a discount percentage?
Subtract the sale price from the original price, divide by the original price, and multiply by 100. Example: ($100 − $80) ÷ $100 × 100 = 20% discount. Use our Discount % mode for instant results.
What is the formula for percent off?
Discount Amount = Original Price × (Discount % ÷ 100). Sale Price = Original Price − Discount Amount. For example, $200 at 25% off = $200 × 0.25 = $50 discount, sale price is $150.
How do you calculate 20% off a price?
Multiply the original price by 0.20 (which is 20/100). For a $50 item: $50 × 0.20 = $10 discount. Final price = $50 - $10 = $40. Or multiply by 0.80 directly: $50 × 0.80 = $40.
How do I find the original price before a discount?
Divide the sale price by (1 − discount %). Example: If you paid $68 after a 15% discount, the original price was $68 ÷ 0.85 = $80.
How do you find the original price from a sale price?
Divide the sale price by (1 - discount percentage). If a shirt costs $30 after 25% off: $30 ÷ 0.75 = $40 original price. The formula is: Original Price = Sale Price ÷ (1 - Discount/100).
Does a 50% + 20% discount equal 70% off?
No! Stacked discounts apply sequentially. 50% off takes $100 to $50, then 20% off the $50 takes it to $40 — only 60% off total, not 70%.
Are stacked discounts cumulative?
No. Stacked discounts are applied sequentially, not added together. 20% off + 10% off equals 28% total savings (not 30%). The second discount applies to the already-reduced price.
What does 'stacked discount' mean?
A stacked discount is when multiple discounts are applied one after another to the same item. Each discount is applied to the reduced price, not the original.
Should I include tax in the discount calculation?
Discounts typically apply to the pre-tax price. However, some stores apply coupons after tax. Our calculator lets you toggle tax on or off so you can see both scenarios.
What's the difference between a percentage discount and a fixed discount?
A percentage discount scales with price (25% off $200 = $50 savings), while a fixed discount is the same regardless of price ($10 off is always $10). Percentage discounts are better for expensive items; fixed discounts are better for cheap items.
Discount Calculator Pros & Cons
Pros
- ✅ Instant savings & final price calculation
- ✅ Supports any discount percentage
- ✅ Stacked discount comparison mode
- ✅ Free forever — no subscriptions
- ✅ Works offline after page load
Cons
- ✗ No bulk/batch discount calculation
- ✗ No currency conversion support
Reviewed by Shahid
Content Reviewer & Calculator SpecialistContent reviewer specializing in marketing, finance, health, and math calculators on GM Calculator.
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