Discount calculator
Find the price after 25 % off 80, the discount rate from an original and a final price, or the original price before a discount.
- Runs in your browser
- No upload
- Instant result
Assumptions & formula
Formula and assumptions
F = O × (1−r/100); r=(O−F)/O ×100
Results
Enter values and press Calculate to see the result here.
How to use this calculator
- Set inputs and units
Choose final price, discount rate or original price, and follow the field labels for that mode.
- Calculate
Check this worked example: price: original=200, rate=25% → final=150, savings=50
- Results
Read the final price and the savings separately. Reversing a discount divides by the fraction that remains, not by the discount itself.
Questions and limits
Can I recover an original price after 100% off?
No. When the final price is zero, no unique original price remains, so reverse mode rejects a 100% rate.
Which input errors should I correct?
Use non-negative prices. In rate mode the final price can't exceed the original, and an ordinary discount is 0–100%.
What does this calculation leave out?
Simple price arithmetic. It doesn't assume tax, stacked coupons, a retailer’s rounding or currency conversion.