How to Use This Discount Calculator
Calculate sale prices, find discount percentages, or reverse-calculate original prices in seconds.
Choose Your Calculation Mode
Select what you want to calculate: Find Sale Price (original + discount%), Find Discount % (from two prices), Find Original Price (reverse calculation), or Stacked Discounts (multiple discounts).
Enter Your Values
Input the required values based on your mode. Use quick percentage buttons (10%, 20%, 30%, etc.) for common discounts.
Add Tax (Optional)
Click "Include Tax" to add sales tax to your final price. The calculator shows tax amount and total separately.
View Your Results
Instantly see your sale price, savings amount, and discount percentage. Results update in real-time.
Pro Tip: After calculating your discounted price, use our Margin Calculator to see how the sale affects your profit margins.
Why Understanding Discounts Matters
Discount calculations are fundamental to both shopping and selling. Whether you're a consumer trying to figure out the final price during a sale, or a retailer planning promotional pricing, knowing how to calculate discounts accurately saves money and prevents costly mistakes.
This discount calculator goes beyond simple percentage calculations. It handles multiple scenarios: finding the sale price from an original price and discount percentage, reverse-calculating the original price from a sale price, determining what discount was applied between two prices, and even calculatingstacked discounts (like 20% off plus an extra 10%).
For ecommerce sellers, discount pricing directly impacts profit margins and break-even points. A 30% discount doesn't just reduce price—it can dramatically affect whether a sale is profitable. Understanding these calculations helps you price promotions strategically.
How to Calculate Discount: Complete Formula Guide
Learning how to calculate discount percentage and sale prices involves a few key formulas. Once you understand these, you can handle any discount scenario—from simple percentage off to complex stacked promotions.
Calculate Sale Price from Discount Percentage
The most common discount calculation: you know the original price and the discount percentage, and need to find the final sale price.
Basic Discount Formula
Calculate the final price after applying a percentage discount.
Sale Price = Original Price × (1 - Discount%/100)Quick Calculation Shortcut
For 20% off: Multiply by 0.80 (or 80%)
For 30% off: Multiply by 0.70 (or 70%)
For 50% off: Multiply by 0.50 (or 50%)
Example: $75 with 20% off = $75 × 0.80 = $60
Two-Step Method
Alternative method: first calculate the discount amount, then subtract from original price.
Discount Amount = Original Price × (Discount%/100) Sale Price = Original Price - Discount AmountCalculate Discount Percentage from Two Prices
When you see a sale tag showing original and sale prices but not the percentage off, use this formula to find the discount percentage.
Discount Percentage Formula
Calculate what percentage discount was applied between two prices.
Discount % = ((Original Price - Sale Price) / Original Price) × 100Find Original Price (Reverse Discount Calculation)
The reverse percentage calculator helps when you know the sale price and discount percentage but need to find the original price before the discount was applied.
Reverse Discount Formula
Calculate the original price from a discounted sale price.
Original Price = Sale Price / (1 - Discount%/100)Reverse Calculation Example
A shirt is marked $56 after a 30% discount. What was the original price?
Original Price = $56 / (1 - 0.30) = $56 / 0.70 = $80
The original price was $80, and you're saving $24.
How to Calculate Stacked (Double) Discounts
Stacked discounts or double discounts occur when multiple percentage discounts are applied sequentially. This is common during sales events: "Take an extra 20% off already reduced prices!"
Important: Stacked discounts are NOT additive. A 20% discount plus a 10% discount is NOT 30% off. The second discount applies to the already-reduced price.
Stacked Discount Formula
Apply multiple discounts sequentially. Each discount applies to the price after the previous discount.
Final Price = Original × (1 - Discount1/100) × (1 - Discount2/100)Stacked vs. Combined Discount
$100 item with 20% + 10% stacked:
$100 × 0.80 × 0.90 = $72 (28% total discount)
If discounts were simply added (30%):
$100 × 0.70 = $70
The stacked method results in a $2 higher price. This matters for both shoppers and sellers!
Combined Equivalent Discount
Calculate the single equivalent discount percentage from multiple stacked discounts.
Combined % = 1 - (1 - D1/100) × (1 - D2/100)Common Discount Percentages Quick Reference
Here's a quick reference table for the most common discount percentages. These multipliers make mental math easier when shopping or pricing products.
| Discount % | Multiplier | $50 Item | $100 Item | You Save |
|---|---|---|---|---|
| 10% off | × 0.90 | $45.00 | $90.00 | $10 per $100 |
| 15% off | × 0.85 | $42.50 | $85.00 | $15 per $100 |
| 20% off | × 0.80 | $40.00 | $80.00 | $20 per $100 |
| 25% off | × 0.75 | $37.50 | $75.00 | $25 per $100 |
| 30% off | × 0.70 | $35.00 | $70.00 | $30 per $100 |
| 40% off | × 0.60 | $30.00 | $60.00 | $40 per $100 |
| 50% off | × 0.50 | $25.00 | $50.00 | $50 per $100 |
| 75% off | × 0.25 | $12.50 | $25.00 | $75 per $100 |
Calculating Discount with Sales Tax
When calculating discounted prices with sales tax, the order of operations matters. In most jurisdictions, tax is applied to the final sale price (after discount), not the original price.
Discount with Tax Formula
Apply tax to the discounted price to get the final amount due.
Final Total = Sale Price × (1 + Tax Rate/100)Discount + Tax Example
$80 item with 25% discount and 8% sales tax:
Step 1: Sale Price = $80 × 0.75 = $60
Step 2: Tax Amount = $60 × 0.08 = $4.80
Step 3: Final Total = $60 + $4.80 = $64.80
You save $20 off the original price, then pay tax only on the discounted amount.
Real-World Discount Examples
Example 1: Black Friday Sale
A $199 jacket is marked 40% off for Black Friday.
Example 2: Double Discount (Stacked)
An item is 30% off, plus a member coupon for extra 15% off the sale price.
Example 3: Finding the Original Price
A clearance item is marked $42 'after 30% off'. What was the original price?
Common Discount Calculation Mistakes
Adding Stacked Discounts
20% + 10% off is NOT 30% off. Each discount applies to the reduced price from the previous discount. 20% then 10% = 28% total, not 30%.
Applying Tax Before Discount
Tax should be calculated on the sale price, not the original price. Applying tax first means paying more than you should.
Confusing Markup with Discount
A 20% markup and 20% discount don't cancel out. If you mark up $100 by 20% ($120) then discount 20%, you get $96—not $100. Use our Markup Calculator for markup calculations.
Ignoring Margin Impact
For sellers: A 30% discount doesn't reduce profit by 30%—it could eliminate your margin entirely. Always check your profit margin and break-even point before running promotions.
Pro Tips for Discount Calculations
For Shoppers: Compare Unit Prices
"Buy 2, Get 1 Free" is effectively 33% off. "Buy 1, Get 1 50% off" is only 25% off. Always calculate the per-unit price to compare deals accurately.
For Sellers: Know Your Break-Even Discount
Calculate the maximum discount you can offer while still making profit. If your margin is 40%, any discount over 40% means selling at a loss. Use our Break-Even Calculator.
Use the Multiplier Method
Instead of calculating discount amounts, multiply by the remaining percentage. For 25% off, multiply by 0.75. For 40% off, multiply by 0.60. It's faster and less error-prone.
Frequently Asked Questions
Ready to Calculate Your Discounts?
Use our discount calculator above to find sale prices, calculate percentages, or reverse-engineer original prices. Combine with our margin calculator to understand the full impact on your bottom line.
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