Discount, Tax & Tip Calculator (Free)
A discount calculator multiplies the original price by (1 − discount ÷ 100). For $80 at 25% off, you pay $80 × 0.75 = $60 and save $20. Sales tax then goes on the sale price: 8% of $60 is $4.80, so the total is $64.80. Stacked discounts multiply too, so 20% then 10% off is 28% off, not 30%.
$80.00 at 25% off costs $60.00 plus $4.80 tax, so you pay $64.80. You save $20.00.
Show steps
- Change the discount to a decimal: 25% = 0.25.
- Amount saved: $80.00 × 0.25 = $20.00.
- Sale price: $80.00 − $20.00 = $60.00. Shortcut: multiply by 1 − 0.25 = 0.75.
- Tax on the discounted price: $60.00 × 0.08 = $4.80.
- Add it up: $60.00 + $4.80 = $64.80.
Each amount is rounded to the nearest cent, the way a register does. Tax rates vary by state and city, so check your local rate.
How to use the discount, tax and tip calculator
- Pick what you want to find: the sale price (with optional tax and tip), stacked discounts, the original price from a sale price, the discount % from two prices, or a dollars-off coupon.
- Type the prices and percents. Leave tax or tip blank if they do not apply.
- Read the total, the amount you save and the sale price. The bars show what you pay, what you save and what tax adds.
- Open Show steps to see each multiplication, rounded to the cent the way a register does.
For tax-only questions, such as working backward from a receipt total, use the sales tax calculator. To split a restaurant bill between several people, use the tip calculator. For any other percent problem, try the percentage calculator.
Discount formulas
- Amount saved = original price × discount ÷ 100
- Sale price = original price × (1 − discount ÷ 100)
- Discount % = (original − sale) ÷ original × 100
- Original price = sale price ÷ (1 − discount ÷ 100)
- Combined discount of d₁ then d₂ = 1 − (1 − d₁)(1 − d₂), with each discount written as a decimal
Worked examples
Example 1: percent off with sales tax
A jacket costs $80 and is 25% off. Saved: $80 × 0.25 = $20. Sale price: $80 − $20 = $60, or in one step $80 × 0.75 = $60. With 8% sales tax, the tax is $60 × 0.08 = $4.80, so you pay $64.80.
Example 2: stacked discounts, 20% then 10%
A $120 item is 20% off, and a coupon takes another 10% off at the register. After the first discount: $120 × 0.8 = $96. After the second: $96 × 0.9 = $86.40. You keep 0.8 × 0.9 = 0.72 of the price, so the combined discount is 28%. Adding the percents would promise 30% off, or $84, which is $2.40 too low. The order does not matter: 10% then 20% also gives $86.40.
Example 3: find the original price
You paid $68 after 15% off. You paid 85% of the original, so the original is $68 ÷ 0.85 = $80. A common mistake is to add 15% of $68 back on, which gives $78.20. That is wrong because the 15% was taken from the larger original price.
Example 4: find the discount percentage
A price drops from $80 to $60. You save $20, and $20 ÷ $80 = 0.25, so it is 25% off. Always divide by the original price. Dividing by the sale price ($20 ÷ $60 ≈ 33.33%) gives the markup back up, not the discount.
Example 5: a discount, tax and tip on one restaurant bill
A $64 dinner has a 15% off promotion, the sales tax rate is 8.875% and you leave a 20% tip. Discounted bill: $64 × 0.85 = $54.40. Tax: $54.40 × 0.08875 ≈ $4.83. Tip on the discounted bill before tax: $54.40 × 0.20 = $10.88. Total: $70.11. Many people tip on the full bill before the discount, since the server did the same work; that tip is $12.80 and the total is $72.03. The calculator lets you choose either.
Percent off quick reference
| Discount | You pay | Price of a $50 item | You save |
|---|---|---|---|
| 10% off | 90% | $45.00 | $5.00 |
| 15% off | 85% | $42.50 | $7.50 |
| 20% off | 80% | $40.00 | $10.00 |
| 25% off | 75% | $37.50 | $12.50 |
| 30% off | 70% | $35.00 | $15.00 |
| 40% off | 60% | $30.00 | $20.00 |
| 50% off | 50% | $25.00 | $25.00 |
| 60% off | 40% | $20.00 | $30.00 |
| 75% off | 25% | $12.50 | $37.50 |
Stacked discounts are not added
| Discounts | Adding them says | Real combined discount |
|---|---|---|
| 20% then 10% | 30% | 28% |
| 25% then 15% | 40% | 36.25% |
| 20% then 20% | 40% | 36% |
| 30% then 20% | 50% | 44% |
| 40% then 10% | 50% | 46% |
| 50% then 50% | 100% | 75% |
The combined discount is always smaller than the sum, because each later discount is taken from a lower price. Two 50% discounts leave a quarter of the price, not zero.
Percent off or dollars off?
To compare a dollars-off coupon with a percent-off deal, turn the coupon into a percent. $10 off a $45 item is $10 ÷ $45 ≈ 22.22% off, which beats 20% off ($9). On a $60 item, 20% off is $12, which beats the $10 coupon. The break-even point is where the percent of the price equals the coupon: 20% of $50 = $10.
Is sales tax charged before or after a discount?
A store’s own discount or coupon normally lowers the price that is taxed, so tax is worked out on the sale price, as this calculator does. Manufacturer coupons can be different. Massachusetts, for example, excludes both retailer and manufacturer coupons from the taxable price, while North Carolina’s published directive treats a manufacturer’s coupon as partial payment, so tax is based on the price before that coupon. Rules vary, so check your receipt or your state’s department of revenue. Results here are estimates for planning and homework, not tax advice.
Common mistakes with discounts
| Mistake | How to catch it |
|---|---|
| Adding stacked discounts (20% + 10% = 30%) | Multiply the “you pay” parts: 0.8 × 0.9 = 0.72, so 28% off. |
| Adding the percent back to find the original price | Divide by the part you paid: $68 ÷ 0.85, not $68 × 1.15. |
| Dividing by the sale price to find the discount % | The discount is a percent of the original price. |
| Taxing the original price after a store discount | Find the sale price first, then add tax. |
| Rounding too early | Keep full decimals and round to the cent only for each amount you would see on a receipt. |
| An answer bigger than the original price | A discount always lowers the price. Check that you subtracted. |
On homework, work the problem by hand first, then use the calculator to check. If the answers differ, compare your working with the steps line by line to find the first difference.
Discounts, tax and tip practice quiz: 10 questions
Test yourself with 10 multiple-choice questions. Choose an answer and press Submit to see if you are right and why. Your score appears at the end.
You keep 0.8 × 0.9 = 0.72 of the price, so the discount is 1 − 0.72 = 28%.
You paid 75%, so the original is $45 ÷ 0.75 = $60. Adding 25% of $45 gives $56.25, which is wrong.
Saved $15, and $15 ÷ $50 = 0.3 = 30%. Dividing by $35 gives about 42.86%.
Quiz complete
Frequently asked questions
How do I calculate a discount quickly in my head?
Find 10% by moving the decimal point one place left, then build from it. For 30% off $45: 10% is $4.50, so 30% is $13.50, and the sale price is $31.50. For 25% off, take a quarter: $80 ÷ 4 = $20 off.
How do you calculate tax and tip on a restaurant bill?
Find the tax on the food total (after any discount), then the tip, usually on the pre-tax amount, and add all three. For a $54.40 bill with 8.875% tax and a 20% tip: $4.83 tax, $10.88 tip, $70.11 total.
Do tax and tip rates change by state or city?
Sales tax rates do: states, counties and cities set their own, so enter the combined rate for where you shop. Tip percentages are a custom, not a law, and people choose their own.
Is 20% off then 20% off the same as 40% off?
No. You pay 0.8 × 0.8 = 0.64 of the price, so it is 36% off. On a $100 item that is $64, not $60.
How do I find the original price from a sale price?
Divide the sale price by the fraction you paid. After 30% off you pay 0.7, so a $49 sale price means an original price of $49 ÷ 0.7 = $70.
Sources
Checked November 2026.
- Massachusetts Department of Revenue, 830 CMR 64H.1.4: Discounts, Coupons and Rebates
- North Carolina Department of Revenue, Sales and Use Tax Directive SD-98-1 (discount cards and coupons)
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