Discount Calculator: Find The Sale Price And How Much You Save

Sales, coupons and clearance tags all use the same simple math, but stacked deals and "buy one, get one" offers can be confusing. This guide shows how to work out any discount quickly, how to tell the real savings from the advertised ones, and how sales tax fits in. Every example was checked in Python.

The Discount Formula

The sale price is the original price minus the discount amount. You can find it in one step or two.

Two steps:

1. Discount amount = original price × discount rate
2. Sale price = original price − discount amount

One step:

Sale price = original price × (1 − discount rate)

For 25 percent off $80:

• Two steps: $80 × 0.25 = $20 saved, then $80 − $20 = $60.
• One step: $80 × 0.75 = $60.

The one-step version is faster on a phone calculator. To use it, subtract the discount percent from 100 and multiply by that number as a decimal. For 25 percent off, you pay 75 percent, so multiply by 0.75.

How To Use The Discount Calculator

The discount calculator above answers the three questions shoppers ask most.

1. Sale Price: "What will I pay?" Enter the price and the discount, plus tax if you want the checkout total.
2. Stacked Deals: "What do two coupons or a BOGO deal really save?" Add each discount in order.
3. Find the Discount: "What percent off is this?" or "What was the original price?"

Every result shows the math, so you can check a price tag or receipt on the spot.

Mental Math Shortcuts For Percent Off

You can estimate most discounts in your head by starting from 10 percent. Move the decimal point one place left to get 10 percent, then build from there.

For odd prices, round first. A $49.99 jacket at 30 percent off is close to $50 × 0.3 = $15 saved, so about $35. For other percent problems outside of shopping, the percentage calculator covers every case.

Dollar-Off Discounts

A dollar-off discount subtracts a fixed amount, no matter the price. To compare it with a percent-off deal, turn it into a percent: discount percent = dollars off ÷ original price × 100.

$15 off a $60 item is 15 ÷ 60 = 0.25, or 25 percent off. The same $15 off a $150 item is only 10 percent off.

That is why "$10 off $50" and "20% off" are worth the same on a $50 cart, but the percent deal is better if you spend more. On a $100 cart, 20 percent off saves $20, while $10 off saves only $10.

How To Find The Discount Percentage

To find what percent off a sale price is, divide the amount saved by the original price: percent off = (original − sale) ÷ original × 100.

A coat drops from $120 to $90:

1. Amount saved: $120 − $90 = $30.
2. Divide by the original: $30 ÷ $120 = 0.25.
3. Percent off: 25 percent.

Always divide by the original price, not the sale price. Dividing by $90 would give 33 percent, which overstates the deal.

How To Find The Original Price

To find the price before a discount, divide the sale price by the share you paid: original price = sale price ÷ (1 − discount rate).

An item costs $63 after 30 percent off. You paid 70 percent of the original, so the original was $63 ÷ 0.70 = $90.

A common mistake is adding 30 percent back to $63, which gives $81.90. That is wrong, because 30 percent of $63 is smaller than 30 percent of the original $90.

Stacked Discounts: Why 20% + 10% Is Not 30%

When two percent discounts stack, the second one applies to the already reduced price. So the total savings are always less than the two percents added together.

$100 with 20 percent off, then an extra 10 percent off:

1. After 20 percent off: $100 × 0.80 = $80.
2. After another 10 percent off: $80 × 0.90 = $72.
3. Total savings: $28, or 28 percent, not 30 percent.

To find the combined percent quickly, multiply the "you pay" parts: 0.80 × 0.90 = 0.72, so you pay 72 percent and save 28 percent. A "50 percent off, plus take an extra 20 percent" sale works out to 0.50 × 0.80 = 0.40, so you pay 40 percent and save 60 percent, not 70.

For two percent discounts, the order does not matter. You get $72 either way.

When The Order Of Discounts Changes The Price

The order matters when you mix a percent discount with a dollar coupon. Take a $100 item with 20 percent off and a $10 coupon:

Taking the percent first gives the lower price, because the dollar coupon is not shrunk by the percent. Stores set the order in their terms, but it helps to know what to expect at checkout.

BOGO And Multi-Buy Deals

"Buy one, get one" and multi-buy deals are discounts spread across several items. To compare them, figure out the effective percent off for everything you buy.

With two $20 items on BOGO free, you pay $20 for $40 worth of goods, which is 50 percent off each. With "buy one, get one 50 percent off," you pay $20 + $10 = $30 for $40 of goods, which is 25 percent off. If items have different prices, the free or discounted item is usually the cheaper one, so the real savings are smaller.

"3 for $10" deals are about the unit price. At 3 for $10, each item costs about $3.33. If the regular price is $3.79, you save about 46 cents per item. Many stores still charge $3.33 if you buy just one, so check the fine print before loading up.

Discounts And Sales Tax

In most U.S. stores, sales tax is added after the discount, so you pay tax only on the sale price. To find the checkout total, apply the discount first, then multiply by (1 + tax rate).

An $80 item at 25 percent off with 7 percent sales tax:

1. Sale price: $80 × 0.75 = $60.
2. Tax: $60 × 0.07 = $4.20.
3. Total: $60 + $4.20 = $64.20.

Sales tax rates differ by state and city, and so do the rules for how coupons are taxed. A store discount and a manufacturer coupon can be treated differently in some places. Your receipt shows exactly which amount was taxed.

Discount Vs Markup

A markup raises a price by a percent of the cost. A discount lowers a price by a percent of the current price. Because they use different starting points, the same percent up and down does not cancel out.

If a store buys an item for $100 and marks it up 25 percent, the price is $125. A 20 percent discount brings it back to $125 × 0.80 = $100. A 25 percent discount would take it below cost, to $93.75.

This is also why "prices were raised 50 percent, then cut 50 percent" leaves you paying less than the start. $100 up 50 percent is $150, and down 50 percent is $75.

How Discounts Affect A Business's Profit

For a seller, a discount comes straight out of profit, so it takes more extra sales than most people expect to make up for it.

Say an item sells for $100 and costs $60 to make, for a $40 profit. With 20 percent off, it sells for $80, and the profit drops to $20 per item. The store now needs to sell twice as many items just to earn the same total profit.

Businesses also use discounts for early payment. Terms like "2/10, net 30" mean the buyer can take 2 percent off if they pay within 10 days, or pay the full amount within 30 days. On a $1,000 invoice, paying early saves $20. To compare that with the cost of borrowing, the simple interest calculator shows how interest adds up over a few weeks.

Is It A Real Deal?

A big percent off is only a deal if the original price was real. Comparing the sale price with what the item actually sells for is the best check.

The Federal Trade Commission's Guides Against Deceptive Pricing say a "former price" in an ad should be the actual, bona fide price the item was offered at on a regular basis for a reasonable period. A "was" price set briefly just to make a markdown look bigger can be misleading.

A few checks help:

• Look at the unit price. A bigger box at "20 percent off" can still cost more per ounce than a smaller one. The unit converter helps compare sizes in different units.
• Compare across stores. The sale price matters more than the percent.
• Watch for "up to" sales. "Up to 70 percent off" means at least one item has that discount, not all of them.
• Count the full cost. Shipping, required add-ons or a membership fee can erase a small discount.

Common Discount Mistakes

Most discount mistakes come from adding percents or using the wrong base.

Summary

• Sale price = original × (1 − discount rate). You save original × discount rate.
• Start from 10 percent for quick mental math.
• Percent off = savings ÷ original price. Original price = sale price ÷ (1 − rate).
• Stacked percents multiply, so 20% + 10% is 28% off. With a dollar coupon, the order can change the price.
• BOGO free is 50% off each item, while BOGO 50% off is 25% off overall. Tax is usually charged on the sale price.

Next step: enter your price and discount in the discount calculator at the top of this page, or explore every tool on the Calc Solver homepage.

Frequently Asked Questions