Your supplier sends a list of a thousand prices with a 15% coupon and you must show the final price of each tomorrow. Doing it on a phone calculator would take you all afternoon.
How to use Discount Formula step by step
1. Choose what to calculate
Final price, amount taken off, percentage applied, original price before the discount, two discounts in a row or a selling price with a markup.
2. Enter price and percentage
Use the price cell and the discount as a number, for example 15 for 15%, or point to a cell already formatted as a percentage.
3. Copy and drag
Paste the formula beside your price list and drag it down to apply the same discount to every item.
The Step Count: Traditional Friction vs. KorexTools
Working out discounts on a phone calculator (4 steps)
- Multiply the price by the percentage.
- Subtract the result from the price.
- Note the value in the sheet.
- Repeat a thousand times for every item.
With the KorexTools “Discount Formula” builder (3 steps)
- You choose the calculation you need.
- You type the percentage and the price cell.
- You copy the formula and drag it down the whole list.
A 15% discount is not subtracted: you multiply by what remains
The most common mistake is subtracting the percentage from the price as if they were the same units. The correct move is to multiply the price by one minus the discount: with 15%, by 0.85. The same logic works backwards: to find the original price before the markdown you divide the final price by that same factor.
When there are two discounts in a row, such as a promotion and then a coupon, they do not add up: the second applies to the price that already came out of the first. A 15% and then a 10% amount to 23.5% overall, not 25%. The builder handles that chaining and also the opposite step, the markup on cost.
Which formula answers each doubt
- •What does it cost now?: price times one minus the discount.
- •What percentage did they give me?: price minus discounted price, over the price.
- •What did it cost before?: discounted price over one minus the discount.
An item priced at 80 with a 15% discount in A2
| Question | Formula | Result |
|---|---|---|
| Final price | =A2*(1-15/100) | 68 |
| Amount taken off | =A2*15/100 | 12 |
| Original price | =A2/(1-15/100) | 94.12 |
Common Mistakes and How to Avoid Them
- ⚠️Typing 0.15 in a %-formatted cell and getting 0.15%.
- ⚠️Adding two discount percentages instead of chaining them.
Frequently Asked Questions
How do I apply a discount to a whole column?
Write the formula in the first row with a relative reference to the price and drag it. If the percentage sits in a fixed cell, anchor that reference with $.
Why does the discount percentage come out as 0.15?
Because Excel returns the fraction. Apply percentage format to the cell to see it as 15%.
Are two 10% discounts a 20% discount?
No: they are 19%, because the second applies to a price that already dropped. Use the two-discounts option to calculate it properly.
What I would do if I were in your shoes
«Two discounts in a row never add up to one discount with the sum of their percentages.» — DataKorex Engineering Team.