What this calculates
Enter the original price and the percentage off, and this shows what you pay and what you save, updating as you type. The proportion bar splits the original price into those two parts, so you can see at a glance how much of the tag the discount actually removes.
It also compares your price across the discounts you meet most often — 10, 20, 25, 30 and 50 percent — which is the fastest way to sanity-check whether a sale is generous.
The formula
A discount is a percentage of the original price, subtracted from it.
What you save
Saving = price × (percent ÷ 100)What you pay
Final price = price − savingIn one step
Final price = price × (1 − percent ÷ 100)The one-step form is the quicker way to do it by hand: 35% off means you pay 65% of the price, so multiply by 0.65 and stop.
Worked example
Now the trap. Suppose a 1,000 item is 30% off, and at the till there is a further 20% off. That is not 50%. The first discount takes it to 700, and the second takes 20% of 700 — not of 1,000 — so you pay 560. The real discount is 44%, six percentage points short of what the signs imply.
When to use it, and the mistakes to avoid
Use it while shopping, when checking a receipt, when comparing two offers on the same item, and when a seller quotes a discount rather than a price.
The mistakes that cost the most:
- Adding stacked discounts. 30% then 20% is 44%, not 50%. Apply them one after the other, in order.
- Trusting the 'was' price. A large percentage off an inflated original is not a saving. Compare against the recent real selling price.
- Confusing percent off with percent of. 25% off means you pay 75%. Those are different numbers and it is easy to compute the wrong one.
- Forgetting tax and delivery. The discount applies to the item, not to shipping, and tax is usually charged on the reduced price afterwards.
- Reversing a discount by adding it back. Adding 25% to a discounted price does not restore the original — the percentage is being taken from a smaller base.
FAQ
How do I work out a discount in my head?
Find 10% by moving the decimal point one place left, then build from it. 30% is that number tripled; 25% is a quarter, so halve the price twice; 15% is 10% plus half of 10%. For 2,999 at 30%: 10% is 300, so the saving is about 900 and you pay about 2,100.
Do two discounts add together?
No, and this is where shops make their money. 30% off followed by a further 20% off is not 50% off — the second discount applies to the already-reduced price, so you get 44% off in total. Stacked discounts are always worth less than they look.
Is the discount taken before or after tax?
In most places the discount comes off first and tax is charged on the reduced price. This calculator deals only with the discount; it applies no GST, VAT or sales tax. If your receipt shows tax added afterwards, run the result through a tax calculator separately.
How do I check whether a sale price is a real bargain?
Work backwards. Take the sale price and the claimed original, and ask what percentage the saving represents. If a 4,500 item is 'reduced' to 2,925, that is a genuine 35% off. Inflated 'was' prices are the oldest trick in retail, so compare against what the item actually sold for recently, not against the tag.
What is the difference between a discount and a margin?
A discount is calculated from the selling price; a margin is calculated from the cost. Taking 25% off a price does not remove 25% of the seller's profit, and marking an item up 25% then discounting it 25% does not return it to the original price — it lands below it.
Can a discount be more than 100%?
Not meaningfully. At 100% the item is free, and anything beyond that would mean the shop paying you to take it. This calculator caps the discount at 100% and tells you when it has done so.