How it works
Multiply the starting value by the percentage and divide by 100. Subtract that amount for a discount or add it for an increase. Percentage change between two values divides the difference by the starting value.
Finance / HXD Labs
Percentage calculator
Find a percentage of a value and compare prices before and after a discount or increase.
Result
Fill in the fields to see the result.
How to use
Enter the initial value and percentage. The tool shows the percentage amount, price after discount and price after increase. Add a final value to calculate percentage change.
Example
For a $100 item with a 15% discount, the discount is $15 and the final price is $85.
Good to know
A 20% discount followed by a 20% increase does not return to the original price, because the second percentage uses a different base.
Quick reference table for percentages and multipliers
| Percentage | Simplified fraction | Decimal | Discount factor | Increase factor |
|---|---|---|---|---|
| 5% | 1/20 | 0.05 | × 0.95 | × 1.05 |
| 10% | 1/10 | 0.10 | × 0.90 | × 1.10 |
| 15% | 3/20 | 0.15 | × 0.85 | × 1.15 |
| 20% | 1/5 | 0.20 | × 0.80 | × 1.20 |
| 25% | 1/4 | 0.25 | × 0.75 | × 1.25 |
| 50% | 1/2 | 0.50 | × 0.50 | × 1.50 |
Frequently asked questions
How do you calculate a percentage discount in one step?
Multiply the starting price by (1 − rate/100). For a 15% discount on $200, multiply 200 by 0.85 to get $170.
How do you find the percentage change between two numbers?
Subtract the initial value from the final value, divide by the initial value and multiply by 100: ((Final − Initial) ÷ Initial) × 100.
Why do two successive 10% discounts equal 19% instead of 20%?
Because the second 10% discount applies to the already reduced 90% balance (0.90 × 0.90 = 0.81), leaving 81% of the original price, or a 19% total discount.