How the Discount Calculator Works
Shops advertise discounts in many forms: 25% off, $10 off with a coupon, buy one get one half off, or two competing offers. It is not always easy to tell what you will really pay, or which offer is better. The Discount Calculator works out the final price for three common cases.
Mode 1: a percent off and a dollar coupon
Enter the price of one item, the quantity, a percent off and an amount of dollars off. The calculator takes the percent off the price, and the dollars off the order:
after the percent = price x (1 - percent off / 100) final price = after the percent - dollars off (never below zero)
The order matters. You can choose which one comes first. Taking the percent first usually gives a slightly lower price when the coupon is a fixed amount, because the percentage is taken from the higher figure.
For example, an $80 item is 25% off, with a $10 coupon. Percent first: $80 x 0.75 = $60, then $10 off gives $50. You save $30, which is 37.5%. Dollars first: $80 - $10 = $70, then 25% off gives $52.50. You save $27.50.
If you buy several items, the dollar coupon comes off the whole order, not each item. Three $80 items with 25% off and a $10 coupon cost $240 x 0.75 - $10 = $170. With 8% sales tax, which is charged on the discounted price, the total is $183.60.
Mode 2: buy some, get some at a discount
Deals like "buy one, get one 50% off" or "buy two, get one free" are groups. Enter how many items you must buy at full price, how many then get the discount, and the discount. The calculator counts how many of your items fall into a discounted slot:
group size = items at full price + items at a discount discounted items = complete groups x discounted items per group + any extras in the last, partial group total = full-price items x price + discounted items x price x (1 - discount)
Say each item is $80 and the deal is buy one, get one 50% off:
| Items you buy | You pay | Price each |
|---|---|---|
| 1 | $80.00 | $80.00 |
| 2 | $120.00 | $60.00 |
| 3 | $200.00 | $66.67 |
| 4 | $240.00 | $60.00 |
The full 25% saving only comes when you buy an even number of items. With one item, there is no saving at all. With "buy two, get one free", four items cost $240, which is 25% off the $320 price.
Mode 3: which of two deals is better?
Enter two offers, each with a percent off, dollars off, or both. The calculator works out what you pay under each, and shows which saves more. A percent discount and a dollar discount change places as the best deal, depending on the price. If one deal is only a percent and the other only a dollar amount, there is a price where they are equal:
break-even price = dollars off / (percent off / 100)
Take 30% off against $25 off. The break-even price is $25 / 0.30 = $83.33. Below that price, $25 off is better. Above it, 30% off is better.
| Price | You pay with 30% off | You pay with $25 off | Better deal |
|---|---|---|---|
| $60 | $42.00 | $35.00 | $25 off |
| $80 | $56.00 | $55.00 | $25 off |
| $100 | $70.00 | $75.00 | 30% off |
| $150 | $105.00 | $125.00 | 30% off |
| $250 | $175.00 | $225.00 | 30% off |
Chart: how much each deal saves
The savings from 30% off grow with the price. The savings from $25 off stay the same:
Price 30% off $25 off $40 ██████ $12 █████████████ $25 $60 ██████████ $18 █████████████ $25 $80 █████████████ $24 █████████████ $25 $100 ████████████████ $30 █████████████ $25 $150 ████████████████████████ $45 █████████████ $25 $250 ████████████████████████████████████████ $75 █████████████ $25
Tips
- Check the order of the discounts. A store's coupon rules decide which comes first.
- Buy-one-get-one deals only save money if you really need the second item.
- Compare the price per item, not the size of the percentage.
- A big discount on a raised price is not a good deal. Compare with the usual price, or with other shops.
What this calculator does not include
- Limits and exclusions in a store's coupon rules, such as a maximum discount or items that do not qualify.
- Different prices for different items in the same order. Each mode uses one price for the item.
- Shipping costs, membership fees and cash-back offers.
- Tax rules that differ by place. Sales tax is applied to the discounted total.
This tool gives an estimate for general information only. The price at the register is the price that counts.