🏷️ Discount / Percent Off

About this calculator

The Discount and Percent Off calculator finds sale prices fast. Enter the original price and discount percentage; it shows the amount saved and the final price, and can stack a second discount or add tax. It also reverses the math to find the original price from a sale price.

Tip: retailers sometimes inflate the original price before a sale — check the price history, because 30 percent off a marked-up price can be worse than no sale at all.

Percentages stack by multiplying, not adding

The single most useful fact about discounts is that successive percentage cuts apply to the shrinking price, not the original one. A 30% discount followed by an extra 10% off is not 40% off. The second discount is calculated on what remains after the first, so the combined saving is always less than the sum of the two numbers. Retailers know this, which is why "extra 10% off sale prices" sounds bigger than it is.

The same logic makes some deals weaker than they look. "Buy one, get one 50% off" is really 25% off a pair of equally priced items: two $60 items cost $90 instead of $120. "Up to 70% off" means the deepest cut in the store is 70%, on possibly a handful of items, while most of the rack sits at 20% or 30%.

A worked example

A jacket is priced at $189.99 with 30% off. The discount is $57.00, so the sale price is $132.99. At the till, an extra 10% comes off the sale price: that is $13.30 more, leaving $119.69. Your total saving against the original price is $70.30, which works out to 37%, not the 40% your brain added up.

Tax is charged on the discounted price for store promotions in Canada, so Ontario HST at 13% applies to $119.69, adding $15.56. You walk out having paid $135.25 for a jacket that would have cost $214.69 at full price with tax. The percentage saved is the same before and after tax; only the dollar figures grow.

It also pays to ask what the discount is a percentage of. Outlet stores and perpetual sale events often price against a suggested retail figure that the item rarely, if ever, sold for. A loyalty program can quietly change the math too: points earned on a discounted purchase are usually calculated on the amount paid, not the tag price, so a 40% sale also shrinks the value of the points you collect. None of this makes a deal bad. It simply means the only trustworthy number in the store is the final price at the till, compared against the final price of the same item somewhere else.

Watch out for these traps

• Anchoring on an inflated regular price. A permanent sale often means the reference price was never the real price. Judge the final dollar figure against what competing stores charge, not against the crossed-out number.
• Mixing up percentage points and percent. A discount moving from 10% to 12% rose by two percentage points, which is a 20% increase in the discount itself.
• Spending more to save more. A discount on something you would not have bought at full price is not a saving; it is a purchase. The math only rewards you on items already in your plans.

Frequently asked questions

What is the fastest way to work out a discounted price?

Multiply the price by what remains after the discount. For 30% off, you pay 70%, so multiply by 0.7. For 15% off, multiply by 0.85. This one step gives the sale price directly, and it works for any percentage. Then confirm by checking that the discount amount plus the sale price equals the original price.

If a store offers 30% off and then an extra 10% off, is that 40% off?

No. The second discount applies to the already reduced price, not the original. Thirty percent off $100 leaves $70, and 10% off $70 removes another $7, for a price of $63. Your total saving is 37%, not 40%. Successive percentages always combine to less than their sum, and the gap grows as the percentages get bigger.

Is sales tax charged on the price before or after a store discount?

For store promotions in Canada, tax is charged on the discounted price, the amount you actually pay for the item. That means a discount saves you the tax on the discounted portion as well. Manufacturer coupons can be treated differently, so the taxable amount on a coupon transaction may be based on the price before the coupon.

What does 'up to 70% off' actually mean?

It means the single deepest discount in the store reaches 70%, while everything else is reduced by less, sometimes much less. The phrase advertises the best case, not the typical one. Check the tag on the specific item you want and judge the deal by its final price compared with other stores, not by the banner.