Guide · Decrease
Percentage Decrease Calculator
Updated: June 2026
A percentage decrease measures how much smaller a number has become relative to its starting point. It is the figure behind a markdown, a budget cut, a drop in traffic or a shrinking balance. The formula mirrors the increase version exactly — only the direction of the subtraction flips — but a few quirks of decreases are worth knowing before you trust the result.
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The percentage decrease formula
To measure the decrease from an original value to a smaller, new one:
As with increases, the original value is the denominator. If you simply use the signed change formula (new − old) ÷ old × 100 you will get a negative number, and the minus sign is what tells you it is a decrease. Both readings are correct; the version above just keeps the result positive when you only care about the size of the drop.
A worked example
A jacket marked at $120 is reduced to $90. The drop is 120 − 90 = 30. Divide by the original price: 30 ÷ 120 = 0.25. Multiply by 100 and the jacket is 25% off. To apply a known reduction instead, multiply by one minus the rate: a 25% cut on 120 is 120 × 0.75 = 90.
Subtracting a percentage fast
The multiplier method is the quickest route. Removing 30% means multiplying by 0.70; removing 8% means multiplying by 0.92. It also makes stacked reductions easy: a 20% cut followed by a further 10% off is 0.80 × 0.90 = 0.72, a 28% total reduction — not 30%.
| Decrease | Multiplier | Applied to 200 |
|---|---|---|
| 5% | 0.95 | 190 |
| 10% | 0.90 | 180 |
| 25% | 0.75 | 150 |
| 50% | 0.50 | 100 |
| 75% | 0.25 | 50 |
The 100% ceiling
Unlike an increase, a decrease has a natural limit. A positive value can fall at most to zero, which is a 100% decrease — you cannot remove more than all of something. If a calculation appears to show a decrease above 100%, the numbers have crossed zero into negative territory, which is a sign change rather than a deeper cut, and the percentage figure stops being meaningful.
Where you'll use it
- Reading a sale tag and confirming the advertised reduction.
- Tracking a fall in sales, visitors or costs against a previous period.
- Working out depreciation on a vehicle or piece of equipment.
- Comparing a reduced offer to its original list price.
Frequently asked questions
What is the percentage decrease formula?
Subtract the new value from the original, divide by the original, then multiply by 100: (old − new) ÷ old × 100.
How do I subtract 30% from a number?
Multiply by 0.70. Subtracting 30% from 200 gives 200 × 0.70 = 140.
Can a percentage decrease be more than 100%?
No. A value can fall at most to zero, which is a 100% decrease.
Do two reductions add together?
No — they compound. A 20% cut then a 10% cut is 0.80 × 0.90 = 0.72, a 28% total reduction.