Finance Discount calculator
Work out a sale price, stack two discounts correctly, or find what percentage off you actually got.
You pay
$60.00
Saving $20.00.
You save
25.0%
- Original
- $80.00
- You pay
- $60.00
- Saved
- $20.00
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Cite this page
Reembun. (2026, July 28). Discount calculator. https://reembun.com/discount-calculator
How to use it
Choose what to work out
One discount, two discounts stacked on each other, or what percentage off two prices actually represent.
Enter the price and the discount
For a stacked sale, the second discount applies to the already reduced price, which is why two 20% cuts are not 40%.
Read the saving
You save shows the money off, alongside the price you actually pay at the till.
The three questions
What do I pay? Multiply by what remains after the discount.
final = price × (1 − discount ÷ 100)What do I pay after two discounts? Multiply the remaining fractions together.
final = price × (1 − d₁ ÷ 100) × (1 − d₂ ÷ 100)What percentage did I get off? Divide the saving by the original price.
percent = (original − paid) ÷ original × 100Stacked discounts are worth less than they look
This is the single most useful thing to know about discounts, and retailers rely on people not knowing it.
| First | Then | Feels like | Actually |
|---|---|---|---|
| 20% | 10% | 30% | 28% |
| 30% | 20% | 50% | 44% |
| 40% | 25% | 65% | 55% |
| 50% | 50% | 100% | 75% |
| 25% | 25% | 50% | 43.75% |
The reason is that the second discount is calculated on a smaller number. After 50% off, the remaining half is all the second 50% has to work on, so it removes a quarter of the original, not another half.
A worked example: a $200 coat at 30% off is $140. A further 20% off takes it to $112. That is 44% off the original, not 50%.
Discount before or after tax
Order matters here, unlike between two discounts.
A $100 item with a 20% discount and 8% sales tax:
- Discount then tax: $80 × 1.08 = $86.40
- Tax then discount: $108 × 0.8 = $86.40
They come out the same, because both are just multiplication. What is not the same is a discount that applies only to the pre-tax amount versus a coupon deducted from the post-tax total. The latter saves you the tax on the discounted amount as well. Read the coupon terms.
Working backwards
Finding the original price from a sale price catches people out, because the instinct is to add the percentage back.
An item cost $60 after 25% off. The $60 represents 75% of the original:
original = 60 ÷ 0.75 = $80Adding 25% to $60 gives $75, which is $5 short. The error grows with the discount: at 50% off, adding back gets you nowhere near.
Reference discounts
| Off | You pay | On $100 |
|---|---|---|
| 10% | 90% | $90 |
| 15% | 85% | $85 |
| 20% | 80% | $80 |
| 25% | 75% | $75 |
| 33% | 67% | $67 |
| 50% | 50% | $50 |
| 60% | 40% | $40 |
| 70% | 30% | $30 |
| 75% | 25% | $25 |
A useful sanity check when a sign says “up to 70% off”: the phrase means at least one item is 70% off, and says nothing about the rest.
Common questions
Why is 20% off then 10% off not 30% off?
Because the second discount applies to the already-reduced price, not to the original. The remaining fractions multiply rather than add, so 0.8 × 0.9 leaves 0.72, so you pay 72% and save 28%, not 30%. The gap widens with larger discounts. 50% then 50% is 75% off, not 100%.
Does the order of two discounts matter?
No. Multiplication is commutative, so 20% then 10% gives exactly the same price as 10% then 20%. What does matter is the order of a discount and a tax, because tax is usually applied to the discounted price, so a discount before tax saves you the tax on the discount too.
How do I find the original price from a sale price?
Divide, do not add the percentage back. If an item cost $60 after 25% off, the original was 60 ÷ 0.75 = $80. Adding 25% to $60 gives $75, which is wrong. This is the same arithmetic trap as removing sales tax from a total.
Is a bigger percentage always the better deal?
Only on the same starting price. 40% off a $100 item saves $40, while 50% off an $70 item saves $35. Compare the final prices, not the percentages, and be wary of a discount applied to an inflated reference price.
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