How to Calculate a Discount and the Sale Price
By Tools Star Hub Editorial Team · Published
Quick answer: multiply the original price by the discount percentage and divide by 100 to get the amount you save. Subtract that saving from the original price to get the sale price. For 25% off 80, the saving is 80 × 25 ÷ 100 = 20, and you pay 80 − 20 = 60. A shortcut is to multiply by what remains: 80 × 0.75 = 60.
Shop signs, coupon codes and checkout banners all express savings as a percent, but your budget works in money. Turning “30% off” into an actual amount tells you whether the deal is worth it, lets you compare offers that are written differently, and catches the occasional mistake at the till.
What does a percentage discount mean?
A percentage discount is a reduction measured against the original, list, or regular price. “20% off” means you pay 20 out of every 100 less than the starting price. The money taken off is the discount amount, and what is left is the sale price or final price.
Two figures matter, and they are easy to mix up. The discount rate is the percent, such as 20%. The discount amount is the money, such as 15 off a 75 item. The calculator shows both: the large figure is the final price and the line underneath is the discount amount.
What is the discount formula?
Discount amount = original price × discount rate ÷ 100. Sale price = original price − discount amount. If you prefer one step, sale price = original price × (100 − discount rate) ÷ 100.
The one-step version is handy for mental arithmetic. For 15% off, you pay 85%, so multiply by 0.85. For 40% off, you pay 60%, so multiply by 0.6. For 10% off, move the decimal point one place to the left to find the saving, then subtract it.
| Discount | You pay | Saving | Final price |
|---|---|---|---|
| 10% off | 90% of the price | 12 | 108 |
| 15% off | 85% of the price | 18 | 102 |
| 20% off | 80% of the price | 24 | 96 |
| 25% off | 75% of the price | 30 | 90 |
| 33% off | 67% of the price | 39.60 | 80.40 |
| 50% off | 50% of the price | 60 | 60 |
| 70% off | 30% of the price | 84 | 36 |
How do stacked discounts work?
When a shop offers “an extra 10% off sale prices”, the second discount usually applies to the already reduced price, not to the original. Twenty percent off and then ten percent off is not thirty percent off. On a 100 item, the first cut leaves 80, and 10% of 80 is 8, so you pay 72. That is a combined saving of 28%.
To check a stacked offer, multiply the remaining shares together. Paying 80% and then 90% means paying 0.8 × 0.9 = 0.72 of the price. The order does not matter for two percentage cuts, but it does matter when one of the discounts is a fixed amount. Taking 10 off before a 20% discount on a 100 item leaves 72, while taking 20% off first and then 10 leaves 70.
With the calculator, run the first discount, copy the final price, paste it back in as the new original price, and apply the second discount. Read the store’s terms, because some shops apply each code to the original price instead.
Should the discount come before or after sales tax?
For a straight percentage discount and a percentage tax, the final number is the same either way, because multiplication can happen in any order. 100 with 20% off and then 8% tax is 100 × 0.8 × 1.08 = 86.40, and adding tax first gives the same total.
What changes is how much tax you pay, and whether a coupon is applied before or after tax in the store’s system. Tax rules vary by place, so this guide does not say which order a given shop must use. To see the tax on a discounted price, run the discount here and then use the Sales Tax Calculator on the final price.
How do I find the original price from a sale price?
Divide the sale price by the share you paid. If a jacket costs 63 after 30% off, you paid 70% of the original, so the original was 63 ÷ 0.7 = 90. Checking it the other way, 30% of 90 is 27, and 90 − 27 = 63.
If you know both prices and want the discount rate, use the percentage change formula: (sale − original) ÷ original × 100. From 90 to 63 is −30%, which is a 30% discount. The Percentage Change Calculator does that step for you.
How do I compare different kinds of deals?
Convert every offer into the price you would pay for the same quantity. “Buy one, get one half price” on two 40 items costs 40 + 20 = 60 for two, which is the same as 25% off both. “Three for the price of two” is the same as paying two-thirds, or about 33% off each item, but only if you wanted three.
A fixed-amount coupon, such as 15 off orders over 100, is worth 15% on a 100 basket and 10% on a 150 basket. When you compare it with a percentage offer, work out both final prices on the basket you actually plan to buy.
How to use the Discount Calculator
- Enter the original price. Type the price before any reduction, using digits and a decimal point only. A currency symbol, a comma, or a negative number is rejected with a message.
- Enter the discount percentage. Type the percent off, from 0 to 100. Decimal rates such as 12.5 work. Anything above 100 is refused, because the price cannot fall below zero.
- Press Calculate. The large figure is the final price, rounded to two decimal places for display. The line underneath shows the discount amount.
- Copy the final price or reset. The copy button copies the final price as shown. Reset clears both fields. The calculation runs in your browser and nothing is stored.
Example
A 35% off sweater
Original price 48, discount 35%. The saving is 48 × 35 ÷ 100 = 16.80 and the final price is 31.20. The calculator shows 31.2 as the main figure and 16.8 as the discount amount.
Checking a stacked online sale
A 250 item is 40% off, with an extra 15% at checkout. First pass: 250 at 40% gives 150. Second pass: 150 at 15% gives 127.50. The total saving is 122.50, or 49% of the original price, not 55%.
Splitting the bill after a group discount
A dinner for four costs 180 before a 10% loyalty discount. The final price is 162, which is 40.50 each. Divide the final price, not the original, before you add a tip.
Tips and limitations
Rounding
Results are displayed to two decimal places. A shop may round each line item or round only the total, so a receipt can differ from your own figure by a cent or two.
One discount at a time
The calculator applies a single percentage. For stacked offers, run it again on the reduced price, as shown above.
Fixed-amount coupons
A coupon worth a set amount is plain subtraction, so you do not need the percentage tool for it. To see what percent it represents, divide the coupon by the price and multiply by 100.
Look at the price you started from
A large percentage only helps if the original price was a real price. Comparing the final price with other shops tells you more than the size of the percent off.
FAQ
- How do I work out 20% off in my head?
- Find 10% by moving the decimal point one place left, double it, and subtract. For 65, 10% is 6.50, 20% is 13, and the sale price is 52.
- What is the difference between the discount rate and the discount amount?
- The rate is the percent, such as 25%. The amount is the money taken off, such as 20 on an 80 item. The calculator shows the amount under the final price.
- Is 20% off and then another 20% off the same as 40% off?
- No. Paying 80% twice is 0.8 × 0.8 = 0.64 of the price, which is a 36% total discount.
- How do I find what percent off I got?
- Divide the saving by the original price and multiply by 100. A 90 item sold for 72 saved 18, and 18 ÷ 90 × 100 = 20%.
- How do I find the price before the discount?
- Divide the sale price by the share you paid. A 51 price after 15% off came from 51 ÷ 0.85 = 60.
- Can I enter a discount with decimals, like 12.5%?
- Yes. Any rate from 0 to 100 with a decimal point is accepted.
- Does the calculator include sales tax or VAT?
- No. It only applies the discount. Use the Sales Tax Calculator on the final price if you need tax added.
- Is buy one, get one free the same as 50% off?
- Only if you wanted two. You pay for one and receive two, so each item costs half, but you still spend the full price of one item.
- Why does my receipt differ by a cent from the calculator?
- Stores may round each item separately before totaling. The calculator rounds the single result to two decimal places.
- What does 0% discount return?
- The final price equals the original price and the discount amount is 0. That can be a quick way to check you typed the price correctly.
- How do I apply a percent off and then see the savings amount?
- Enter the original price and discount percent; read both the final price and the money saved.
- How should stacked coupon discounts be applied?
- Apply them in the order the store states—usually one after another on the reduced price, not added percents.
- Can I calculate the pre-discount price from a sale tag?
- Yes—enter the sale price and percent off, then solve backward for the original when the tool supports it.
- Does sales tax change the discount percent?
- Tax is usually added after the discounted price; the percent off still refers to the pre-tax item price unless noted.
- How do I compare 25% off versus $20 off?
- Run both against the same original price and pick the lower final price.
- What is a quick mental check for 15% off?
- Take 10% then half of that 10% and add them; subtract the sum from the original.
- How do member-only prices fit in?
- Treat the member price as another discount scenario and compare it to the public sale percent.
- Why might online and in-store finals differ?
- Rounding, tax jurisdiction, or excluded fees can change the receipt even with the same listed percent.
- Can I include shipping in the discount base?
- Only if the promotion says so; most item discounts exclude shipping.
- How do I handle a discount cap like “up to $50 off”?
- Compute the percent savings, then clamp the dollar savings at the cap before subtracting.
Work out any sale price with the free Discount Calculator. It shows the final price and the amount you save.
To see the rate between two prices, use the Percentage Change Calculator.
To add tax to a reduced price, try the Sales Tax Calculator.