Percentage Decrease Calculator
Calculate the new value after a percentage decrease. Enter the original value and percentage to subtract — full step-by-step working shows the multiplier method used in GCSE maths.
After 15% decrease
170
How it works
Find the multiplier
A 15% decrease uses a multiplier of 0.85. Subtracting from 1 removes the 15% from the original.
Result:0.85Multiply by the original value
Multiply 200 by 0.85 to find the reduced value.
Result:170Check: the decrease amount
The actual decrease is 30, which is 15% of 200.
Result:-30
The formula
Example substitution
A 15% decrease: multiply by 0.85. Original 200 becomes 170.
Worked examples
A £60 item is reduced by 20% in a sale. What is the sale price?
- 1Multiplier: 1 − 20/100 = 0.8
- 2Multiply: 60 × 0.8 = 48
A car worth £12,000 depreciates by 15%. What is it worth now?
- 1Multiplier: 1 − 15/100 = 0.85
- 2Multiply: 12000 × 0.85 = 10200
A 75 kg person loses 8% of their body weight. Find their new weight.
- 1Multiplier: 1 − 8/100 = 0.92
- 2Multiply: 75 × 0.92 = 69
Frequently asked questions
How do you calculate a percentage decrease?+
Multiply the original value by (1 − percentage/100). E.g., decrease £80 by 15%: 80 × 0.85 = £68.
What multiplier gives a 30% decrease?+
0.70 — multiply by 0.70 to decrease by 30%.
How do you calculate a sale price?+
If an item is 25% off, multiply the original price by 0.75.
Can a percentage decrease be more than 100%?+
No — a 100% decrease results in zero. A decrease greater than 100% is not possible for positive values.