Discount Calculator

How to use the discount calculator

The first choice, Calculate, sets the direction of the sum.

• Apply discount: you know the offer and want the price. Select a Discount type, then fill in the boxes that appear for it.
• Calculate discount: you know the original price and the sale price and want to know how big the reduction is. Enter both and you get the amount saved and the percentage.

Prices are rounded to the cent in the answer. Whole amounts appear without decimals, such as $60, and other amounts with two, such as $10.50.

Types of offer the calculator handles

Offers like "half price on the second item" usually apply to the lowest-priced item in the basket, which is how the calculator treats them, so the order in which you type the prices does not matter. The percentage reported for multi-item offers is measured against the full price of everything in the basket.

Discount formulas

sale price = original price × (1 − discount ÷ 100)

savings = original price × discount ÷ 100

discount % = (original price − sale price) ÷ original price × 100

A fixed-amount discount is simply a subtraction, and dividing the amount by the original price gives its percentage equivalent. To undo a percentage discount and recover the original price, divide the sale price by (1 − discount ÷ 100). These are the same ideas as in the general percentage calculator, and the percent off calculator and percent decrease calculator cover close variations.

Worked examples

Percent off. A jacket costs $249.99 and is 35% off. Savings: 249.99 × 0.35 = $87.4965, shown as $87.50. Sale price: 249.99 × 0.65 = $162.4935, shown as $162.49.

Finding the discount. A $120 item is marked down to $84. You save 120 − 84 = $36, which is 36 ÷ 120 = 30%. Working back, 84 ÷ 0.70 = $120 recovers the original price.

Fixed amount. A voucher takes $15 off a $60 order. The price becomes $45, and the voucher is worth 15 ÷ 60 = 25%.

2 for 1. Two shirts cost $30 and $18. You pay $30 and save $18, which is 18 ÷ 48 = 37.5% of the full price of $48.

3 for 2. Three books cost $12, $18 and $25. The cheapest is free, so you pay 12 + 18 + 25 − 12 = $43 and save $12, which is 12 ÷ 55 = 21.82%.

50% off the second item. Two items cost $80 and $60. The cheaper one is halved, saving $30. You pay $110 instead of $140, a reduction of 30 ÷ 140 = 21.43%.

Things to watch for

• Discounts do not add. Taking 20% off and then a further 10% leaves 0.80 × 0.90 = 0.72 of the price, a total discount of 28%, not 30%. Apply each discount in turn.
• Undoing a discount needs a bigger percentage. A 25% price cut is reversed by a rise of 1 ÷ 0.75 − 1 = 33.3%, not 25%.
• Compare per-unit prices. A big percentage off a larger pack can still cost more per unit than a smaller one at full price.
• Tax and shipping. Sales tax is generally calculated on the discounted price, but rules vary. To add tax to the result use the VAT calculator, and remember shipping fees may sit outside the offer.
• Fake anchors. A "was" price that was never charged makes any percentage off meaningless; compare with what you saw elsewhere.

If you are on the selling side and want to know what a discount does to profit, compare it with your profit margin first: a 20% discount on a product with a 30% margin removes two thirds of the profit on each sale.