Discount Calculator
A discount reduces the original price by a percentage. Free online calculator with instant results.
You pay
$800
You save
$200
Discount amount
$200
Effective %
20%
Method
How this calculator works
A discount reduces the original price by a percentage. Stacked discounts apply sequentially — the second discount acts on the already-reduced price.
Single: Sale Price = Original × (1 − Discount/100)
Stacked: After 1st = Original × (1 − D1/100)
After 2nd = After 1st × (1 − D2/100)
Effective % = (1 − (1−D1/100)(1−D2/100)) × 100- Enter the original price of the item.
- Enter the discount percentage.
- Optionally enter a second stacked discount (coupon, loyalty, etc.).
- See the final sale price, total savings, and effective discount percentage.
Examples
Worked examples
Real numbers, end-to-end results.
$1,000 · 20% off
You pay $800 · Save $200
Simple single discount.
$500 · 30% + 10% stacked
You pay $315 · Save $185 · Effective 37%
Double discount is 37%, not 40%.
$2,499 · 15% off
You pay $2,124.15 · Save $374.85
Common electronics sale scenario.
Use cases
When to use it
- Shopping sales — quickly check how much you actually save.
- Comparing competing discounts from different stores.
- Calculating effective discount on stacked coupons.
- E-commerce sellers setting competitive pricing.
FAQ
Frequently asked questions
How is discount calculated?
What is a stacked or double discount?
Why is stacked discount less than the sum of both percentages?
How to calculate the original price from sale price?
How to calculate what percent off something is?
Does the discount calculator work for any currency?
Methodology, assumptions & limitations
How we calculate: This calculator uses standard, peer-reviewed mathematical formulas implemented in TypeScript. All calculations run entirely in your browser — no data is sent to any server.
Assumptions: Unless stated otherwise, calculations assume constant rates over the specified period, no taxes or fees beyond those explicitly input, and standard compounding conventions for the formula type.
Limitations: Results are estimates for planning purposes. Real-world outcomes may differ due to variable rates, regulatory changes, taxes, fees, inflation, or other factors not modeled. This tool does not constitute professional advice.
When NOT to use this: Do not rely solely on this calculator for critical decisions where exact precision is required beyond the decimal places shown.
Feedback: Found an error or have a suggestion? Contact us — we review and correct reported issues within 48 hours.
Deep Dive Guide
How Discounts Are Calculated — Single, Stacked, and Why 20+10 ≠ 30%
The math behind sale prices and stacked discounts. Learn why two consecutive discounts don't simply add up, and how to calculate your real savings.
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