Discount calculator
Free discount calculator for sale prices, stacked percentage discounts and optional sales tax. Compare savings, final prices and practical worked examples.
By Calcr · Updated
Discount calculator: Calculate a sale price
Enter the original price and a percentage discount. Enter sequential rates separated by commas when the offer applies further reductions to the remaining price. Set sales tax to zero to exclude tax, or enter a rate to apply after discounts. The result separates savings before tax, the discounted price, tax and the final amount.
Discount formulas
For one discount, savings = original price * rate / 100 and final price = original price * (1 - rate / 100).
For sequential discounts a% and b%, final price = original price * (1 - a/100) * (1 - b/100). The combined rate is 100 * (1 - (1 - a/100) * (1 - b/100)).
Worked examples
One discount: 25% off 80 saves 20 and leaves 60 to pay.
Two discounts: 20% off 100 leaves 80. Taking another 10% off 80 saves 8 more, so the final price is 72. The total saving is 28%, not 30%.
With tax: a single 30% discount on 100 gives a subtotal of 70. Applying 5% sales tax adds 3.50, making the final price 73.50. With tax set to zero, the sequential 20%-then-10% offer has a final price of 72.
Limits
Enter 1 to 20 discount rates between 0% and 100%; prices cannot be negative. An optional sales-tax rate between 0% and 100% applies after all discounts. Final price = discounted price * (1 + tax / 100). Displayed amounts round half up to two decimal places. Delivery, fixed-amount coupons and merchant-specific fees are not included. A retailer may use different tax or intermediate-rounding rules; check the actual checkout total.
When to use this discount calculator
Use this free discount calculator when a sale is described as one or more percentage reductions from an original price. It separates the reduced item price from the amount saved and from any entered sales tax. This is useful for comparing two offers with the same starting price or checking whether a stacked promotion behaves as advertised under a simple percentage model.
Start with the price that actually receives the discount. A list price, a previously reduced price and a cart subtotal can all be different bases. If an offer excludes certain items or applies only after a minimum spend, check those conditions before entering a number. The calculator cannot read a retailer's terms, decide which products qualify or verify that the original price was genuinely charged.
Do not use it as a complete checkout or tax engine. Fixed-value vouchers, shipping, duties, membership charges, tax-inclusive pricing and store-specific rounding may require separate calculations. The optional tax field applies a single supplied rate after every percentage discount. It does not infer a rate from your location or determine whether a coupon changes a taxable amount under local rules.
Example: comparing a single offer with stacked offers
A product starts at 200. Store A offers 30% off, giving savings of 60 and an item price of 140. Store B offers 20% off followed by another 15% off. The first step leaves 160, and the second leaves 160 * 0.85 = 136. Store B's combined saving is 64, or 32% of the original price. The second offer is four units cheaper before any other charges.
Adding 20% and 15% would incorrectly predict a 35% reduction and a price of 130. The second discount is calculated from 160, so it removes 24 rather than 30. Compare the final prices with identical tax and fee assumptions. A lower item subtotal does not guarantee a lower checkout total if the two stores have different shipping charges or eligibility rules.
Example: tax after a percentage reduction
An item costs 120 before tax and receives a 25% discount. The discounted price is 120 * 0.75 = 90, and the saving before tax is 30. With an entered tax rate of 8%, the tax is 90 * 0.08 = 7.20. The final result is 97.20. Enter the original price, a discount of 25 and tax of 8 to reproduce this scenario.
Without the promotion, applying the same tax assumption would give 120 * 1.08 = 129.60. Comparing the two final totals gives a difference of 32.40, while the tool's “save before tax” detail remains 30. Those figures measure different things. Keep the before-tax label when discussing the displayed saving, and verify the merchant's actual taxable amount rather than assuming this simplified setup applies everywhere.
Price displays round to two decimal places after the underlying calculation. With several small-price items, a shop that rounds each item or each promotion separately can arrive at a slightly different basket total. That difference need not mean the percentage formula is wrong. To investigate, compare the original item base, the sequence of discounts, the taxable subtotal and the rounding stage one by one.
When checking a promotion, test an easy reference first. Ten percent off 100 should save 10; zero percent should leave the price unchanged; 100% should reduce the item subtotal to zero. Then enter your actual numbers. This gives you a quick way to catch a rate entered as 0.25 when you meant 25%, or a previously discounted price accidentally entered as the original base.
To keep a comparison fair, use the same original price in both scenarios. A 30% reduction from 200 leaves 140, while a 25% reduction from 180 leaves 135. The larger percentage discount does not produce the lower final item price because the bases differ. Compare the actual amounts you would pay, and keep tax and delivery assumptions consistent. The saving percentage is useful only alongside its original base. If an offer advertises savings “up to” a rate, enter the rate that applies to your item rather than assuming the advertised maximum.
FAQ
Can I add two discount percentages?
Not when the second applies to the reduced price. Multiply the remaining-price factors instead.
Does discount order matter?
Pure percentage discounts have the same product in either order before rounding. Fixed coupons and store rules can change that.
Does 100% off mean a zero total?
It means a zero item price in this calculation. Separate fees may still apply.
How can I find the original price from a sale price?
For a single discount below 100%, divide the sale price before tax by one minus the discount rate as a decimal. A sale price of 60 after 25% off implies 60 / 0.75 = 80 originally. Use the scientific or percentage calculator for that reverse calculation. Dividing by zero at a 100% discount cannot recover an original price because any original item price could have produced zero.
Can this compare offers with a fixed coupon?
Only after you calculate that coupon under its actual terms separately. Taking ten units off before a percentage discount can differ from taking ten off afterward. Minimum spends, excluded items and tax rules add further conditions. This form accepts percentage reductions only, so do not enter a fixed coupon amount as if it were a percentage. Compare the resulting checkout amounts with all applicable charges included.