Reduction Percentage Calculator
Measure how much something went down in percent: a cost cut, a smaller bill, lower energy use or fewer defects. Enter the original and the reduced value.
Results update as you type.
- Reduction
- 20%
- Amount reduced
- 50
- Remaining share
- 80%
Steps
- (250 − 200) ÷ 250 × 100 = 20%
Worked example
Example: your electric bill drops from $250 to $200
- Reduction = 250 − 200 = 50
- 50 ÷ 250 = 0.20
- × 100 = 20%
That's a 20% reduction.
Formula
Reduction % = (Original − New) ÷ Original × 100
A reduction can never exceed 100% (that would mean the value fell below zero).
Frequently asked questions
How do I calculate percentage decrease?
Subtract the new value from the original, divide by the original, multiply by 100.
If a price is reduced by 20%, what do I pay?
80% of the original. Multiply by 0.8.
How do I reverse a reduction?
Divide the reduced value by (1 − reduction). $200 after a 20% cut came from $200 ÷ 0.8 = $250. See the reverse percentage calculator.
Last reviewed October 17, 2026 · Calculations run in your browser; nothing you enter is sent to a server.