Discount Calculator
Black Friday or end-of-season clearance — but what will you actually pay? Enter the original price and discount to see the final price and your savings, including stacked double discounts.
Calculate Your Discount
| You save | – |
| Effective discount | – |
How to Use the Discount Calculator
Type the original (pre-sale) price and the discount percentage, then press Calculate Discount. You immediately see the final price you will pay, the dollars you save, and the effective discount. Shopping during Black Friday sales or end-of-season clearances, where stores advertise "flat 30% off plus an extra 15% on checkout"? Put the second figure in the optional second-discount box — it is applied to the already-reduced price, exactly like the shop's billing system does.
Use the "you save" figure to sanity-check the deal: if the saving seems too good, verify the original price was genuine and not inflated the week before the sale — a common trick everywhere, from the mall to online stores.
Discount Formula
A single discount is one subtraction: knock the percentage off the price. With two stacked discounts, apply them in sequence — the second discount sees only what remains after the first, which is why stacked percentages never simply add:
Written with decimals, a 20% discount means multiplying by 0.80. Two 20% discounts mean multiplying by 0.80 × 0.80 = 0.64 — you pay 64% and save 36%, not 40%. The order does not matter: 0.80 × 0.80 is the same either way.
Worked Example
A jacket priced at $200 with 20% off, plus an extra 20% off at checkout:
| Step | Calculation | Result |
|---|---|---|
| 1. First discount | 200 × 0.80 | $160 |
| 2. Saving so far | 200 − 160 | $40 (20%) |
| 3. Second discount | 160 × 0.80 | $128 |
| 4. Total saved | 200 − 128 | $72 |
| 5. Effective discount | 72 ÷ 200 × 100 | 36% — not 40% |
The missing 4% ($8) is the discount-on-the-discount: the second 20% was taken off $160, not $200. Stores know this; now you do too.
Stacked Discounts — The Trick Almost Nobody Explains
"Extra 25% off already-discounted prices" sounds like 25% + 30% = 55% off. It is not. Here is what common stacks really give you — the comparison table most deal blogs never publish:
| Advertised stack | Naive sum | Actual effective discount | On $500 you pay |
|---|---|---|---|
| 20% + 20% | 40% | 36.0% | $320.00 |
| 30% + 20% | 50% | 44.0% | $280.00 |
| 50% + 25% | 75% | 62.5% | $187.50 |
| 10% + 10% + 10% | 30% | 27.1% | $364.50 |
The pattern: each extra discount is worth less than its face value because the base keeps shrinking. The general rule is effective = 1 − (1−d1)(1−d2)… — our calculator applies it for you. Two more traps to watch: "up to 70% off" usually means one rack of clearance items, and some stores quietly raise the "original" price before the sale, making the discount fictional. Compute the final price, then compare it across two or three stores before buying.
Limitations
The calculator trusts the original price you enter — it cannot detect inflated "was" prices, which are the oldest trick in retail. It does not add sales tax, shipping or delivery fees, which can erase a thin discount on online orders. Card-specific extra discounts ("10% off with XYZ card") stack the same way mathematically, but often carry caps ("up to $25") that this tool does not model — read the fine print. Percentages are exact; human shopping judgement is not.
A discount is a small, friendly version of a big financial idea: pay less than the headline, keep the difference working. The mortgage extra payments guide runs the same logic at house scale — how an extra $200 a month can save $109,000 in interest.
Frequently Asked Questions
How do I calculate a discount price?
Do two 20% discounts equal 40% off?
How do I find the original price from a sale price?
What is the difference between discount and markup?
Are 'up to 70% off' sale claims honest?
Should I ever buy just because of a discount?
Guides for This Tool
Related Tools
Profit Margin Calculator
Calculate profit margin and markup to price your products correctly.
Loan Calculator
Calculate monthly loan payments and total interest with an amortization schedule.
Compound Interest Calculator
See how savings and investments grow with compounding over time.
Percentage Calculator
Percentages, increases, decreases and ratios in a single click.
Unit Price Calculator
Compare up to 3 products by price per unit — find the real cheapest deal.
US Salary Tax Estimator
Estimate federal income tax and take-home pay from your US salary.