Discount Rate Calculator
Calculate the discount rate between two prices easily. Enter the original price and discounted price to find out the percentage discount.
How to Calculate Discount Rate?
1. Enter the original price
2. Enter the discounted price
3. Click "Calculate Discount Rate"
4. The results will show:
- Discount rate (%)
- Discount amount
- Total savings
Financial Calculations
Recovering the discount rate from two prices
This is the inverse problem: you know what something used to cost and what it costs now, and you want the percentage. The arithmetic is a single division, but which number goes on the bottom decides whether you get a discount rate or a markup rate, and those are never the same figure.
Formula
rate (%) = ((original - discounted) / original) x 100
The denominator is always the original price. Dividing by the discounted price gives the markup needed to reverse the discount, which is a larger number.
A discount and its reversal are not symmetrical
A price cut from 100 to 80 is a 20% discount. Restoring 80 to 100 is a 25% increase. Both describe the same pair of numbers, and both are correct, because percentages are always relative to a base and the base changed.
This asymmetry is the reason a stock that falls 50% needs a 100% gain to recover, and why a 30% pay cut is not undone by a 30% rise. The general relation is that a discount of d% requires a markup of d / (100 - d) x 100 to reverse.
Percentage points are not percentages
If a discount rises from 20% to 25%, that is a 5 percentage point increase but a 25% relative increase in the discount itself. Financial reporting distinguishes the two carefully; retail advertising frequently does not.
The practical test: percentage points compare two percentages by subtraction, percentages compare them by division. When a claim says "25% more discount", ask which operation produced it.
Where the reverse calculation is genuinely useful
- Auditing whether an advertised rate matches the prices actually charged at the till.
- Comparing competing offers where one quotes a percentage and the other a fixed amount off.
- Working out the real cost of a trade-in or part-exchange deal against a cash price.
- Establishing the effective discount on a bundle by comparing it to the sum of individual prices.
- Checking supplier invoices against contracted volume rebate tiers.
- Reconstructing an original price from a sale price and a known rate, which is the same formula rearranged.
Worked example
A monitor was 429.00 and is now 314.00. The saving is 115.00. Dividing by the original: 115 / 429 = 0.2681, so 26.81% off.
Checking the reverse: to return 314.00 to 429.00 requires an increase of 115 / 314 = 36.62%. The two rates differ by nearly ten percentage points from the same pair of prices, which is exactly why the denominator matters.
If the retailer advertised "30% off", the claim is overstated by 3.19 percentage points, and under EU pricing rules the reference price would need to be the lowest price of the previous 30 days.
Discount versus the markup needed to reverse it
| Discount applied | Price after (from 100) | Markup to restore |
|---|---|---|
| 10% | 90.00 | 11.1% |
| 20% | 80.00 | 25.0% |
| 25% | 75.00 | 33.3% |
| 33.3% | 66.70 | 50.0% |
| 50% | 50.00 | 100.0% |
| 66.7% | 33.30 | 200.0% |
| 80% | 20.00 | 400.0% |
The gap widens sharply past 50%, which is why deep discounting is difficult to unwind without customers noticing.
Frequently Asked Questions
Related calculators
References
- EU Directive 2019/2161 (Omnibus Directive) on price reduction announcements
- OECD Glossary of Statistical Terms - percentage change
Last reviewed: 2026-08-07. This page is informational. For legal, medical, tax, or financial decisions, confirm the result with a qualified professional.