Tools
Discount Calculator
Calculate the discounted price in seconds: price + discount percent → new price and savings, with stacked second-discount support. Or find the discount rate from two prices, or the original price from a sale price. Free, no sign-up.
The extra discount applies to the price left after the first one: 50% + 20% is 60% off in total, not 70%. Use it for an extra at-checkout discount or a coupon.
The rate is always measured against the old price. That is why a drop from $800 to $600 is 25% off, while a rise from $600 to $800 is a 33.33% increase. If the new price is higher, the tool shows the increase instead.
Original price = sale price ÷ (1 − rate). An item cut 20% to $400 used to cost $500, not $480. If an extra discount was also applied, enter it in the second field.
Result
Enter the price and pick a discount; the result appears instantly.
- Digital Marketing Expert
- Google Partner
- Full Stack Developer
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How to use the Discount Calculator
- Choose the calculation
Apply discount gives a sale price. Find the rate compares two prices, and Original price works back to the price before a promotion.
- Type the price
Use a point for cents, as in 349.90. A thousands comma is fine too, so 1,250 and 1,250.90 read correctly. A comma followed by exactly three digits counts as a thousands separator.
- Pick the discount
Tap 10%, 20%, 25%, 30% or 50%. Type any other rate, such as 12.5, into the Custom % box. Tapping a preset again clears the custom value.
- Add an extra discount if there is one
Type a second rate, such as a checkout offer or a coupon, into the Extra discount field. The tool takes it off the price that is left after the first discount.
- Read and share the result
The sale price, your saving and the real total rate update as you type. Copy link gives you an address that opens with the same values. That way you can send the calculation to your team.
Discount calculator formulas
The tool uses the formulas below in all three modes. You enter rates as percentages, so for 30% you type 30.
Sale price = Price × (1 − rate ÷ 100)Saving = Price − Sale priceFinal price = Price × (1 − a ÷ 100) × (1 − b ÷ 100)Real rate = [1 − (1 − a ÷ 100) × (1 − b ÷ 100)] × 100Rate = (Old price − New price) ÷ Old price × 100Original price = Sale price ÷ (1 − rate ÷ 100)The tool rounds amounts to two decimals and rates to at most two decimals. Now and then the two discount lines differ from the total saving by one cent. That difference comes from rounding.
Worked discount examples
Each row is a worked example; enter the same values in the tool and you get exactly these results.
| Mode | Inputs | Result | You save | Real discount rate |
|---|---|---|---|---|
| Apply discount | $500, 30% | $350.00 | $150.00 | 30% |
| Apply discount | $100, 50% + extra 20% | $40.00 | $60.00 | 60% |
| Apply discount | $1,250, 30% + extra 10% | $787.50 | $462.50 | 37% |
| Apply discount | $79.99, 25% | $59.99 | $20.00 | 25% |
| Find the rate | $1,200 → $900 | 25% off | $300.00 | 25% |
| Find the rate | $50 → $40 | 20% off | $10.00 | 20% |
| Original price | $400, 20% | $500.00 | $100.00 | 20% |
| Original price | $63, 30% + extra 10% | $100.00 | $37.00 | 37% |
The tool shows plain numbers without a currency sign. In row four it rounds the sale price and the saving separately. Still, the two add up to the list price.
Real total rate of stacked discounts
Use this table to see at a glance what two percentages on a sale banner really add up to.
| First discount | Extra discount | What it looks like | Real total discount | Final price of a $100 item |
|---|---|---|---|---|
| 10% | 10% | 20% | 19% | $81.00 |
| 20% | 10% | 30% | 28% | $72.00 |
| 20% | 20% | 40% | 36% | $64.00 |
| 30% | 10% | 40% | 37% | $63.00 |
| 30% | 20% | 50% | 44% | $56.00 |
| 40% | 25% | 65% | 55% | $45.00 |
| 50% | 20% | 70% | 60% | $40.00 |
| 50% | 50% | 100% | 75% | $25.00 |
You can check any row in Apply discount mode: type 100 as the price and enter both rates.
What does this discount calculator show you?
This discount calculator turns a price and a percentage into three numbers: what you pay, what you save and the real rate of the deal. The maths looks simple, but it gets slippery once discounts stack or a shop shows only the sale price. So I built the tool around three questions.
- Apply discount: enter a price and a rate. You get the sale price, the saving and the real total rate.
- Find the rate: enter the old and new price. The tool returns the discount, or the increase if the price went up.
- Original price: start from the sale price and the rate, then work back to the price before the promotion.
We plan promotions in our e-commerce consulting projects, and the first thing we check is simple. Does the rate on the banner match the number at checkout? Everything here runs in your browser, so no price you type leaves your device.
How do you work out the real rate of stacked discounts?
Retailers love tiered promotions because the eye adds two percentages together without any prompting. However, the second discount always comes off the price that is left after the first one. Worked example: a $1,000 coat drops 40% to $600. An extra 25% at checkout takes $150 off that $600, so you pay $450. In other words, the banner suggests 65% off, but the real discount is 55%.
The general rule: turn each discount into a multiplier of (1 − rate ÷ 100). Then multiply the multipliers. For example, 30% and 10% give 0.70 × 0.90 = 0.63. You pay 63% of the list price, so the real discount is 37%. As a result, the true rate of stacked discounts is always lower than the sum of the two percentages.
- Extra discount at checkout: it comes on top of the product page price; type it into the Extra discount field.
- Percentage coupon: same logic, it comes off whatever is left. A fixed dollar coupon, on the other hand, needs converting to a rate first.
- A third discount: copy the first result back into the price field, then enter the remaining rates in turn.
Want to explore percentages more broadly? The percentage calculator handles a percentage of a number, the share one number is of another and percentage change.
Using the discount calculator in reverse: how do you find the original price?
If a tag shows only the sale price and the rate, you work backwards. Divide the sale price by (1 − rate ÷ 100). Worked example: an item that sells for $400 at 20% off originally cost $400 ÷ 0.80 = $500.
The most common slip is to add the same percentage back on. Adding 20% to $400 gives $480, but the 20% came off $500, not off $400. The gap widens as the rate grows. For instance, an item cut 50% to $250 used to cost $500, not $375.
The Original price mode does this division for you. Did the product also get an extra discount at checkout? Enter it in the second field, and the tool reverses both rates at once. For example, a price of $787.50 after 30% and then 10% off goes back to a list price of $1,250.
I use this check in two situations above all.
- Comparing a competitor's sale price with your own list price.
- Turning a supplier's net price list back into catalogue prices.
Is the was price genuine, and which price should a discount start from?
A discount is only as honest as the price it starts from. In the EU, Article 6a of the Price Indication Directive requires every announced price reduction to show the prior price. That is the lowest price the trader applied in at least the 30 days before the cut. The European Commission's guidance on Article 6a explains the exceptions, for example for goods that spoil quickly. In 2024 the Court of Justice added that an advertised percentage must also start from that prior price.
In the United States, the FTC's Guides Against Deceptive Pricing take a similar line. A former price is a fair basis for comparison only if the seller offered the item at that price in good faith. It also has to last for a reasonably substantial period of time. Worked example: a lamp sells for $100 and drops to $50 for a few days. It then returns to $100, and two weeks later it goes on sale at $40 with 60% off on the tag. Under the EU 30 day rule the prior price is $50, so the honest figure is 20%.
To check a claim, open Find the rate. Enter the lowest recent price as the old price and the sale price as the new one. I also keep website trust signals in mind when I write promotion copy. A customer who spots an inflated rate once will doubt the next campaign too. Rules differ by country and change over time, so check current regulations before a major campaign.
What is the real discount in multi-buy and bundle deals?
Multi-buy offers never state the rate directly, so first work out the totals, then switch to Find the rate. The undiscounted total goes in as the old price, and what you actually pay goes in as the new price. In the worked examples below, one unit costs $100.
- Buy 2, get 1 free: you pay $200 instead of $300. That is a real discount of 33.33%.
- Second item half price: you pay $150 instead of $200. Across both items, that is 25% off.
- $50 off when you spend $500: on a $500 basket that is 10%. On an $800 basket it falls to 6.25%.
- Buy one, get one free: two items for the price of one is 50% off. Yet a customer who wants only one item saves nothing.
For shoppers, this shows whether the extra units are worth buying at all. For sellers, it tells you how much the average order value has to grow before the offer pays off. Do you plan to send discount codes to people who left their carts? My article on strengthening the sales funnel with remarketing covers when a discount actually helps and when it just gives margin away.
How much margin does a discount really cost?
A discount rate and the drop in profit are not the same thing. Worked example: you sell an item for $1,000 that costs you $600, so the unit profit is $400. A 20% discount brings the price to $800 while the cost stays put, and the unit profit falls to $200. In short, a 20% discount wipes out half of the profit on each sale.
To keep the same total profit, you need to sell more units. The multiplier is gross margin ÷ (gross margin − discount rate). With a 40% margin, 40 ÷ (40 − 20) = 2, so you must double unit sales. With a 30% margin, the same discount needs 30 ÷ 10 = 3 times the volume. Once the discount reaches the margin, every sale loses money.
When a promotion runs on paid traffic, add the ad cost to this sum as well. Put the discounted revenue into the ROAS calculator to see where you break even. In our Google Ads management work, we also update target ROAS to the new margin during a sale.
Do you pay sales tax on the full price or the discounted price?
It depends on who funds the discount. The Minnesota Department of Revenue, for instance, applies sales tax after a store coupon. The retailer simply lowers its own price. With a manufacturer coupon, however, tax applies to the full retail price. A third party reimburses the retailer for that coupon. Many US states follow the same logic, but the details vary, so check the rules in your state.
Worked example with a hypothetical 7% sales tax: a $100 item comes with a $20 store coupon. The store charges tax on $80, so the total is $85.60. With a $20 manufacturer coupon, tax applies to the full $100; you pay $80 plus $7 tax, which makes $87.
In the UK and the EU, on the other hand, consumer shelf prices already include VAT. A discount therefore lowers the VAT inside the price in proportion. To split a discounted gross price into net and VAT, use the VAT calculator. It works in both directions.
Common discount calculation mistakes
- ✕MistakeAdding stacked discounts: reading 50% + 20% off as 70% off.✓Do this insteadMultiply the multipliers: 0.50 × 0.80 = 0.40, so the real discount is 60%. In the tool, type the second rate into the Extra discount field.
- ✕MistakeFinding the original price by adding the same rate back: $400 + 20% = $480.✓Do this insteadDivide the sale price by (1 − rate ÷ 100): $400 ÷ 0.80 = $500. Original price mode does this in one step.
- ✕MistakeDividing by the new price: calling a drop from $1,200 to $900 a 33% discount.✓Do this insteadAlways divide the difference by the old price: 300 ÷ 1,200 = 25%. Dividing by the new price gives the increase in the opposite direction.
- ✕MistakeRaising the price just before a sale so that the crossed-out figure looks bigger.✓Do this insteadBase the rate on the lowest price of the last 30 days, as EU rules require. Then advertise that honest rate.
- ✕MistakeTreating the discount rate as the drop in profit.✓Do this insteadRecalculate unit profit at the sale price before you commit. With a 40% margin, a 20% discount halves the profit on every sale.
Frequently Asked Questions
A good discount strategy differs from margin-melting discounts.
In e-commerce a campaign is the balance between protecting margin and lifting sales. Let's design your pricing and campaigns together.
