Choose the right calculation for your situation
Sale price & coupons
Percent off, fixed coupons and ordered discounts.
100 × (1 − 20%) × (1 − 10%) = 72; 100 − 72 = 28
Apply discounts from top to bottom. A 20% discount followed by 10% saves 28%, not 30%. Fixed coupons can apply per item or once per order.
Find the discount %
Compare the original price with the sale price.
(120 − 90) ÷ 120 × 100 = 25%
Sale price cannot exceed the original price in this discount calculation.
Find the original price
Work backward from a sale price and discount.
80 ÷ (1 − 20%) = 100; 20 ÷ 20% = 100
Choose whether you know the sale price or the amount saved. Sale price with a 100% discount has no unique original price. Savings with a 0% discount also cannot determine an original price.
Buy more, get more
Buy X get Y, second or third item discounts.
5 × 10; 3 → 2; 5 − 1 = 4; 4 × 10 = 40
Only eligible items form groups. Each complete group discounts its cheapest item(s); incomplete groups pay full price. Quantity includes free items. Choose grouping and any repeat limit to match the offer.
Discount a shopping cart
Different prices, quantities and eligible items.
100 + 60 × 2 = 220; 220 × 80% × 90% = 158.40
Apply discounts from top to bottom. A 20% discount followed by 10% saves 28%, not 30%. Fixed coupons can apply per item or once per order.
Quantity discount
Apply a discount when the quantity qualifies.
12 ≥ 10; 12 × 100 × 85% = 1,020
Apply a discount when the quantity qualifies.
Stay within a budget
Find the highest unit price after coupons and tax.
138.89 × 80% × 90% ≈ 100.00
Use the seller's tax rule. Inclusive prices already contain tax; exclusive prices add it. Tax rates are entered manually and are not determined by currency.
How to use this calculator
Choose the mode and currency, then enter the labeled inputs. Results update as you type. Load the illustrative example to check the formula; Reset clears the draft.
Formula & assumptions
Final price = Original price × (1 − d₁) × (1 − d₂)
Savings = Original price − Final price
Effective discount (%) = (Original price − Final price) ÷ Original price × 100
Original price = Final price ÷ (1 − d)
Amounts use the currency’s smallest unit. Target-margin prices round upward; discount results round only after all discounts. Zero denominators produce no ratio.
Worked example
Example · illustrative values
Original price: 100 USD; d₁ = 20%, d₂ = 10% → 100 × 0.8 × 0.9 = 72 USD; Savings: 28 USD.
What the result includes
Only eligible items form groups. Each complete group discounts its cheapest item(s); incomplete groups pay full price. Quantity includes free items. Choose grouping and any repeat limit to match the offer. Use the seller's tax rule. Inclusive prices already contain tax; exclusive prices add it. Tax rates are entered manually and are not determined by currency.
Common questions
How do I calculate a sale price and the amount saved?
Multiply the original price by 1 minus the discount rate. For a $100 item with 20% off, the sale price is $100 × 0.80 = $80 and the saving is $20. Enter 20 for the percentage discount, not 80.
How can I find the discount percentage from two prices?
Subtract the sale price from the original price, divide by the original price, then multiply by 100. A price reduced from $120 to $90 gives ($120 − $90) ÷ $120 × 100 = 25% off.
Is 20% off followed by 10% off the same as 30% off?
The second discount applies to the reduced price. Starting at $100, 20% off leaves $80 and another 10% off leaves $72: a total discount of 28%. Add each offer separately in the order the store applies it.
Does the order of a dollar-off coupon and a percentage discount matter?
Yes. On a $100 purchase, taking $10 off before a 20% discount gives $72. Applying 20% first and then taking $10 off gives $70. Check whether a fixed coupon applies once to the order or separately to each eligible item.
How do I work out the original price before a discount?
Divide the sale price by 1 minus the discount rate. If you paid $80 after 20% off, the original price was $80 ÷ 0.80 = $100. A 100% discount leaves no unique original price to recover from a zero sale price.
What percentage discount is buy two, get one free?
For three equally priced items, you pay for two, saving one-third, or about 33.33%. If prices differ and the cheapest item is free, divide that free item's price by the total before the offer. Enter eligible items and the store's grouping rules in the multibuy scenario.
Should tax be calculated before or after the discount?
Use the tax basis shown by the store or invoice. The calculator lets you use the original or discounted amount as the tax base, and handle tax-inclusive prices. Matching those settings matters more than assuming every coupon has the same tax treatment.
Why can the checkout total differ from the calculator?
Check coupon order, eligible items, quantity limits, tax and any shipping or extra charges. Stores may also round each item or each discount separately. The calculator keeps precision through discount steps and rounds the resulting amounts to the selected currency's precision.