Discount Calculator
Find out exactly how much you save with any percentage discount. Calculate sale prices, stacked discounts, and see the final cost including optional tax.
About This Calculator
The Discount Calculator shows you the final price after applying one or two percentage discounts, with optional sales tax. It is useful for shopping sales, comparing deals, and budgeting. The stacked discount feature reveals why taking 20% off then 10% off is not the same as 30% off — a common misconception that costs shoppers money. Enter any combination of discounts and tax rates to see your true out-of-pocket cost.
How to Use
- Enter your values in the input fields above
- Click the calculate button to see results
- Review your results displayed below the inputs
- Use the reset button to clear all fields and start over
The Formula
How the calculation works under the hood
Single discount
Subtract the discount fraction from 1, then multiply by the original price.
Stacked discounts
Apply each discount sequentially. This is NOT the same as adding the two percentages.
Worked Example
Step-by-step walkthrough with real numbers
“A $120 jacket is 25% off, with an additional 10% loyalty discount and 8% sales tax.”
- 1First discount: $120 x 0.25 = $30 off. Sale price = $90.
- 2Second discount: $90 x 0.10 = $9 off. Price = $81.
- 3Tax: $81 x 0.08 = $6.48.
- 4Total you pay: $81 + $6.48 = $87.48.
- 5Total saved: $120 - $81 = $39 (32.5% effective discount).
You pay $87.48 after both discounts and tax, saving $39 off the original price.
⚠️Common Mistakes
- ✕Adding stacked discounts together (25% + 10% = 35%) — the actual combined effect is only 32.5%.
- ✕Applying the discount to the post-tax total instead of the pre-tax price.
- ✕Forgetting to account for sales tax on the discounted price, which can add several dollars.
💡Pro Tips
- ✓Compare the effective total discount of stacked offers: multiply (1-D1) x (1-D2) and subtract from 1.
- ✓During holiday sales, some stores stack store-wide discounts with manufacturer coupons — this calculator shows you the true savings.
- ✓If the tax rate differs by location, enter the exact rate from your receipt to verify the charged amount.
Frequently Asked Questions
How do I calculate a percentage discount?
Multiply the original price by the discount percentage divided by 100, then subtract from the original price. For example, 25% off $80: 80 x 0.25 = $20 savings, sale price = $60.
What are stacked discounts?
Stacked discounts apply one after another. A 20% off then an additional 10% off is NOT the same as 30% off. The second discount applies to the already-reduced price.
How does sales tax affect my final price?
Enter the optional tax rate and the calculator applies it to the discounted price, showing your true out-of-pocket cost.
Why is 20% + 10% off not the same as 30% off?
Because the second discount applies to the already-reduced price. 20% off $100 = $80, then 10% off $80 = $72. That is 28% total savings, not 30%.
Can I calculate the original price from a sale price?
Yes. If you know the sale price and discount percentage, divide the sale price by (1 - discount/100) to find the original.
Is this calculator free to use?
Yes! All calculators on Get Precision Calculator are completely free with no limitations or sign-up required.
Is my data saved or tracked?
No. All calculations are performed locally in your web browser. Get Precision Calculator does not store, collect, or track your calculation data.
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