Percent Off Calculator
This calculator works out how much you save and what you will pay when a percentage discount is applied to a price, and it also works in reverse to tell you what discount rate was used between two prices you already know. Enter the original price and the discount percentage, or pick a common discount from the preset dropdown running from 5% through to 75%, and it instantly returns the dollar saving, the sale price and the original price side by side, along with a comparison table showing what you would pay at every common discount level on the same item. A calculation breakdown and worked example show each step of the maths, from the saving through to the final sale price, plus a check that the two figures add back up to the original. If you already know both the before and after prices, use the reverse section instead: enter the original and sale price, and it works out the exact discount percentage applied. This is handy for checking advertised sale prices or confirming a store has charged you correctly. The results are exact arithmetic and do not account for GST or retailer-specific rounding, so use them as a guide alongside the price actually charged at the till.
1. Price and Discount
2. Reverse: Find the Discount Rate
Already know the original and sale price? Enter both below to find the percentage saved.
Common Discounts at This Price
| Discount | You Save | Sale Price | Saving as % of Original |
|---|
Calculation Breakdown
Worked Example
How to Calculate Percent Off
A percent-off discount reduces an original price by a fraction of itself. The two key formulas are:
- Dollar saving = Original Price x (Discount% / 100)
- Sale price = Original Price x (1 - Discount% / 100)
For example, 25% off $120.00:
- Saving = $120.00 x 0.25 = $30.00
- Sale price = $120.00 x 0.75 = $90.00
This is equivalent to multiplying the original price by the remaining percentage (100% - discount%). A 25% discount means you pay 75% of the original price.
Common Discount Reference Table
| Discount | Fraction equivalent | You pay | Example: $100 item |
|---|---|---|---|
| 10% off | 1/10 | 90% | $90.00 |
| 20% off | 1/5 | 80% | $80.00 |
| 25% off | 1/4 | 75% | $75.00 |
| 33% off | approx 1/3 | 67% | $67.00 |
| 50% off | 1/2 | 50% | $50.00 |
| 75% off | 3/4 | 25% | $25.00 |
Finding the Discount Rate from Two Prices
If you know the original price and the sale price but not the discount percentage, use this formula:
- Discount% = ((Original Price - Sale Price) / Original Price) x 100
For example, an item originally priced at $160 is on sale for $120: Discount% = (($160 - $120) / $160) x 100 = ($40 / $160) x 100 = 25%.
Worked Example Matching Default Inputs
With the default values (original price $120.00, discount 25%):
- Saving = $120.00 x 0.25 = $30.00
- Sale price = $120.00 x 0.75 = $90.00
- Check: $30.00 + $90.00 = $120.00 (matches original price)
Percent Off vs Percentage Decrease
A "percent off" discount and a "percentage decrease" describe the same mathematical operation when the context is price reductions. The only difference is framing: retailers say "30% off"; mathematicians say "a 30% decrease". Both mean the new value is 70% of the original.
Related Calculators
- Maths and Stats Calculators: full hub for percentages, ratios, and number tools.
- Percentage Calculator: find what percent one number is of another.
- Percentage Change Calculator: calculate the increase or decrease between two values.
- Percentage Increase Calculator: find the new value after a percentage increase.
- Percentage Off Plus GST Calculator: apply a discount and then add GST in one step.
Sources and method: Standard arithmetic formula for percentage discounts. Sale Price = Original Price x (1 - Discount / 100). Consistent with New Zealand Consumer Protection guidelines on advertised discounts (consumerprotection.govt.nz) and general retail mathematics.
This calculator provides exact arithmetic results for the inputs supplied. It does not account for GST, tax implications, or retailer-specific rounding. For discounts that include NZ GST, use the Percentage Off Plus GST Calculator.