Percentage Change Calculator
Percentage change calculator
Compare old and new values to find signed percentage change or symmetric percentage difference.
Percentage change
25 %
Signed mode measures gain or loss relative to the previous value baseline. Direction: Increase. Signed mode requires a nonzero previous value because it is the reference baseline.
Signed delta
25
Absolute change
25
Previous value
100
New value
125
Advanced options
- Formula: ((new − previous) / |previous|) × 100.
- Direction: Increase.
- Signed mode requires a nonzero previous value because it is the reference baseline.
Formula
Signed change = ((New - Old) / |Old|) × 100; Symmetric difference = (2 × |New - Old| / (|New| + |Old|)) × 100 \text{Symmetric Difference} = \frac{2|\text{New} - \text{Old}|}{|\text{New}| + |\text{Old}|} \times 100 - Choose signed mode when the previous value should be the baseline.
- Choose symmetric mode when both values should be treated equally.
- Multiply the resulting ratio by 100 to convert it to percent.
Example
Worked example: 80 to 100
- 1 Difference = 100 - 80 = 20
- 2 Ratio = 20 / 80 = 0.25
- 3 Percent change = 0.25 x 100 = 25
The value increased by 25%.
How
- Choose signed percentage change or symmetric percentage difference.
- Enter the previous value and the new value.
- Read the live percentage result, delta, and direction together.
Avoid
- Using the new value as denominator instead of the old value.
- Forgetting to multiply by 100 after dividing.
- Using old value = 0, which is undefined.
FAQ
Can the result be negative?
Yes. A negative value means the new value is lower than the old value.
Why is old value zero not allowed?
Division by zero is undefined, so percent change cannot be computed.
Is this different from percentage difference?
This tool supports both. Signed change uses the old value as the base reference, while symmetric difference treats both values equally.
When should I use symmetric difference?
Use symmetric mode when neither value should be treated as the one true baseline, such as side-by-side comparisons between two measurements.
Switch
Switch12
No match.