About Discount Calculator
Calculate sale prices, savings, and final cost with tax. Supports percentage and flat discounts. Free, no sign-up required.
How to use
- Enter the original price in the Price field. This is the sticker price before any discount is applied — leave any cents in (for example 49.99, not 50).
- Type the discount amount and choose its type from the dropdown. Pick % for a percentage off (20 means 20%) or $ for a flat dollar amount off the price.
- Optionally enter your local sales tax rate. Defaults to 13 (Ontario HST); use 5 for GST-only provinces, 15 for HST in Atlantic Canada, or 0 if tax is already included.
- Read the result panel: it shows the dollar amount saved, the discounted subtotal, the tax owed on the discounted subtotal, and the final price you actually pay at the till.
- For stacked sales (extra 10% off clearance) run the calculator twice: feed the first result back in as the new Price and apply the second percentage. Stacked discounts compound, they don't add.
- To work backwards from a sale price (find the original), divide the sale price by 1 minus the discount as a decimal: $60 after 25% off equals 60 / 0.75 = $80 original.
Examples
30% off a $79.99 jacket with 13% HST
Original $79.99 minus 30% = $23.997 saved, leaving a $55.99 subtotal. HST at 13% on the discounted price adds $7.28, making the final cost $63.27. You saved $24.00 and paid $10.41 less in tax than you would have at full price.
Stacked discount: 50% off plus extra 20% off
On a $100 item, the first 50% drops it to $50. Applying an extra 20% to that $50 takes it to $40 — not $30. Stacked percentages multiply (0.5 × 0.8 = 0.4), so two discounts of 50 and 20 percent equal a single 60% discount, not 70%.
$15 off a $90 grocery order with 5% GST
Flat $15 off $90 leaves $75 subtotal. GST at 5% adds $3.75 (Canada applies GST/HST after the discount per CRA rules), so you pay $78.75 total. The effective discount on your final receipt is $16.50 — you save tax on the $15 you didn't spend.
Frequently asked questions
Should sales tax apply before or after the discount?
In Canada and most US states, GST/HST/PST and sales tax apply to the discounted price, not the original. The CRA rule is explicit: GST/HST is calculated on the consideration actually paid. So a $100 item at 20% off generates tax on $80, not $100. The exception is manufacturer rebates redeemed at the till in some jurisdictions — those can be taxed on the pre-rebate amount. Always check your receipt to confirm which line the tax is calculated on.
Do stacked discounts add together or compound?
They compound, not add. A 50% off coupon followed by an extra 20% off is not 70% off — it is 60%, because the second discount applies to the already-reduced price. Mathematically, two discounts of x% and y% combine to (1 - (1-x)(1-y)) × 100. Stores stack discounts this way because it sounds bigger than it is. Always run the math through both cuts to know your real savings before assuming the percentages add up.
How do I figure out the original price from just the sale price?
Divide the sale price by (1 minus the discount as a decimal). If a jacket is marked $60 after 25% off, the original was 60 / (1 - 0.25) = 60 / 0.75 = $80. For a 40% off price of $42, original = 42 / 0.60 = $70. This is useful when comparing across stores that only show the final marked-down price, or when you want to verify a 'was/now' tag is honest.
How do BOGO and bulk discounts compare to a percentage off?
Buy-one-get-one-free is mathematically a 50% discount on the pair (you pay full price for one of two items), but only if you actually want both items. Buy-one-get-one-50% is a 25% discount on the pair. Bulk thresholds (15% off when you spend $100+) are a strict percentage off the qualifying subtotal. To compare BOGO against a flat 30% off the same items, calculate the per-item cost both ways: 30% off two $40 shirts is $56 total, while BOGO on the same two shirts is $40 total — BOGO wins if you need two.
Can I use this for percentage markup on a sale price?
Not directly — markup goes the other way. Discount calculates a price below the original; markup calculates a price above a cost. If you mistakenly use this tool for markup you'll underprice your inventory. For markup math (cost to selling price), use the dedicated Markup Calculator. The reverse-engineering trick mentioned above (sale price ÷ (1 - rate)) is structurally the same operation as markup, but the direction of the calculation matters for accounting.
What's the difference between a discount and a coupon code?
Functionally none — both reduce the price by a percentage or flat amount. Operationally, coupon codes often stack differently. Some retailers allow one site-wide code per order; others let you stack a clearance markdown plus a percent-off code plus a referral credit. Read the cart subtotal after each code is applied — if the subtotal didn't drop, the code didn't take. This calculator handles either type of discount; just enter the value the code provides.
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