Finance

Discount Calculator

Find the sale price, the original price, and exactly how much you save — including stacked Black Friday-style "extra X% at checkout" deals.

What do you want to find?

Sale price Original price

Original price

Discount (%)

Extra discount stacked at checkout (%) Optional. Use this for "extra 10% off everything in cart" promotions.

Sale price

—

Enter the values to see the breakdown.

How a discount works

A discount is a percentage taken off the original price. "30% off" simply means you pay 70% of the marked price (100% − 30%). The math is: sale price = original × (1 − discount/100). To run it backwards ("the tag says $49 with 30% off, what was the original?"), divide instead: original = sale ÷ (1 − discount/100).

This calculator does both — pick a mode at the top. The headline shows the answer, and the breakdown shows the price, the savings, and the effective percentage off (which can be higher than the sticker discount when discounts stack).

How to use it

Two modes, four inputs:

Pick a mode: Sale price (you know the original and want the final), or Original price (you know the sale price and want to back out the original).
Enter the price and the discount percentage.
Optionally enter a stacked discount — an extra % applied on top, like a coupon code at checkout.
The result updates as you type. Compare the effective discount to the sticker discount when you stack.

Stacked discounts: the trick everyone gets wrong

Two discounts do not add together. "50% off plus extra 20%" is not 70% off — it's 60% off. The second discount applies to the already-discounted price, not to the original. The math is: final = original × (1 − d1/100) × (1 − d2/100).

This trips up shoppers every Black Friday. Stores know the sticker math feels bigger than the real math, which is why "extra X% off in cart" promos are so popular. The good news: with this calculator, you can plug both in and see the actual final price before you commit.

Example. A $100 jacket at "50% off" plus an extra "20% off in cart" costs $40 (not $30). You save $60, an effective 60% off — still a great deal, just not 70%.

Common discounts on a $100 item

Quick reference for shopping at a glance. Multiply or divide by 10 for $10 or $1,000 items — the percentages are linear.

Discount	You pay	You save
10%	$90	$10
20%	$80	$20
25%	$75	$25
30%	$70	$30
40%	$60	$40
50%	$50	$50
60%	$40	$60
70%	$30	$70
75%	$25	$75

Based on a $100 baseline, no tax. Tax is applied to the discounted price in most jurisdictions, so it scales the same way.

Frequently asked questions

Why doesn't "50% off + 20% off" equal 70% off?

Because the second discount is taken from the already-reduced price, not from the original. After 50% off, you pay 50%. Taking another 20% off that smaller amount only saves you another 10% of the original — so the combined effect is 60% off, not 70%.

How do I find the original price from a sale price?

Switch to "Original price" mode at the top, enter the sale price you see and the percentage off, and the calculator does the math: original = sale ÷ (1 − percent/100). You can also tell whether the marked-up "original" is realistic — some retailers inflate it before a sale.

Is sales tax applied before or after the discount?

After. Tax is calculated on the discounted price, not the original. So a 30% off discount also reduces the absolute amount of tax you pay, which is a small but real bonus on top of the headline savings.

What about "buy one get one" (BOGO) deals?

BOGO 100% (the second one free) is effectively 50% off if you wanted both items. "Buy one, get one 50% off" is 25% off when you take both. If you only wanted one item, BOGO isn't a discount on what you bought — it's a discount on a thing you didn't plan to buy.

How do I read "up to 70% off" claims?

Skeptically. "Up to" means the highest discount applies to at least one item — sometimes one item, often the ones you didn't want. Look at the discount on the specific items in your cart, not the marketing banner.

What's a good rule of thumb for "is this really a deal"?

Compare the sale price to the price 2–3 months before the sale, not the listed "original". Browser extensions like Honey, Camelizer, or Keepa do this automatically. Anything under 20% off the recent street price is mediocre; 30–40% is a real deal; 50%+ is genuinely good — assuming the original price wasn't padded.

Discount	You pay	You save
10%	$90	$10
20%	$80	$20
25%	$75	$25
30%	$70	$30
40%	$60	$40
50%	$50	$50
60%	$40	$60
70%	$30	$70
75%	$25	$75

Discount	You pay	You save
10%	$90	$10
20%	$80	$20
25%	$75	$25
30%	$70	$30
40%	$60	$40
50%	$50	$50
60%	$40	$60
70%	$30	$70
75%	$25	$75

Discount Calculator