Percentage Decrease Calculator
Find the percentage drop between two values, calculate a new value after a decrease, or reverse-calculate the original. Three modes for every scenario.
Percentage Decrease
-20.00%
Absolute Decrease -20.00
Formula & Examples
Core Formula
% Decrease = ((Old Value − New Value) ÷ Old Value) × 100
New Value = Old Value × (1 − Decrease% ÷ 100)
Original Value = New Value ÷ (1 − Decrease% ÷ 100)
| Scenario | Old | New | Decrease |
|---|---|---|---|
| Price drop | 200 | 160 | −20% |
| Weight loss | 180 lb | 153 lb | −15% |
| Sales decline | 5,000 | 3,500 | −30% |
| Temperature drop | 80°F | 64°F | −20% |
Frequently Asked Questions
How do I calculate percentage decrease? ▼
Subtract the new value from the old value, divide by the old value, then multiply by 100. Formula: ((Old − New) ÷ Old) × 100.
What is the percentage decrease from 100 to 80? ▼
((100 − 80) ÷ 100) × 100 = 20%. The value decreased by 20%.
How do I find the new value after a 15% decrease? ▼
Multiply the original value by (1 − 0.15) = 0.85. Example: 200 × 0.85 = 170.
What is the difference between percentage decrease and percentage change? ▼
Percentage decrease always returns a positive number representing how much a value dropped. Percentage change is signed (+/-) and works for both increases and decreases.
Can I find the original value if I only know the decreased value? ▼
Yes — use "Find Original" mode. Enter the decreased value and the percentage it decreased by. Formula: Original = New Value ÷ (1 − Decrease%/100).