How does the discount calculator work?
Enter an original price and one or two discounts — either as a percentage or a fixed amount — and the calculator shows the final price, total savings, and a full receipt-style breakdown. A second optional discount always applies to the already-discounted price, which is how stacked promotions work in practice.
All monetary values are rounded to 2 decimal places using standard half-up rounding. Currency formatting follows your browser's locale setting automatically.
How to calculate a discount by hand
For a quick mental check, or when you just need the math without the calculator:
- Convert the discount percentage to a decimal by dividing by 100 (25% becomes 0.25).
- Multiply the original price by that decimal to get the savings amount.
- Subtract the savings from the original price to get the final price.
Example: on a $120 item at 25% off, savings = $120 × 0.25 = $30.00, so the final price is $120 − $30.00 = $90.00.
Discount formulas
Percentage discount
Saving = Original price × (Discount % ÷ 100) Final price = Original price − Saving Example: $120 × 25% → $120 − $30.00 = $90.00 Fixed discount
Final price = Original price − Discount amount Example: $120 − $15.00 = $105.00 Stacked discounts
Subtotal = Original price × (1 − D1 ÷ 100) Final price = Subtotal × (1 − D2 ÷ 100) Example: $100 −20% −10% → $80.00 × 0.90 = $72.00 Common discount percentages at a glance
How much a given percentage off actually saves on a $100 item:
| Discount | You Save | Final Price |
|---|---|---|
| 10% off | $10.00 | $90.00 |
| 15% off | $15.00 | $85.00 |
| 20% off | $20.00 | $80.00 |
| 25% off | $25.00 | $75.00 |
| 30% off | $30.00 | $70.00 |
| 40% off | $40.00 | $60.00 |
| 50% off | $50.00 | $50.00 |
| 70% off | $70.00 | $30.00 |
For any other price, the percentage scales proportionally — use the calculator above for an exact figure.
Stacked discounts vs. combined discounts
Two successive percentage discounts are not the same as adding the percentages together.
A 20% discount followed by a 10% discount gives a final price of $72.00 on
a $100.00 item — not $70.00. The second discount is always
calculated on the reduced subtotal.
| Two Discounts | Sounds Like | Actually Equals |
|---|---|---|
| 20% + 10% | 30% off | 28% off |
| 30% + 20% | 50% off | 44% off |
| 25% + 25% | 50% off | 43.75% off |
| 50% + 50% | 100% off (free) | 75% off |
The gap grows with the size of the discounts — which is exactly why "50% off, then an extra 50% off" is a much smaller deal than it sounds.
Finding the original price from a sale price
Working backward — you know what something costs on sale and the discount percentage, and want the original price — uses a different formula, not simple subtraction:
Original price = Sale price ÷ (1 − Discount % ÷ 100) Example: $90 at 25% off → $90 ÷ 0.75 = $120.00 This is the same $120 item from the example above, worked in reverse — a useful check when a receipt shows the sale price and discount rate but not the original price.
Frequently asked questions
What is the difference between a percentage and a fixed discount?
A percentage discount scales with the price — 20% off a $50 item saves $10, while 20% off a $200 item saves $40. A fixed discount removes the same amount regardless of price — $20 off always saves $20.
Can I enter a discount greater than 100%?
No — percentage discounts are capped at 100%, since a discount of more than 100% would result in a negative price. Fixed discounts are capped at the current amount for the same reason.
Does the Share link include all my inputs?
Yes. The Share button copies a URL containing your original price, both discount types and values, and whether the second discount is active. Anyone opening the link sees the calculator pre-filled with the same values.
How do I calculate a percentage discount without a calculator?
Divide the discount percentage by 100, multiply by the original price to get the savings, then subtract that from the original price. For 25% off $120: 0.25 × $120 = $30 saved, so the final price is $90.
How do I find the original price before a discount was applied?
Divide the sale price by (1 minus the discount as a decimal). A $90 sale price at 25% off gives $90 ÷ 0.75 = $120 as the original price.
Is 20% off plus 10% off the same as 30% off?
No — it works out to 28% off, not 30%. The second discount applies to the already-reduced price, not the original, so stacked percentages never simply add up.
What counts as a "stacked" discount in real stores?
Common examples: a coupon code applied on top of an already-discounted sale price, a loyalty or membership discount combined with a clearance markdown, or a store-wide sale stacked with an additional promo code at checkout.