((new − start) ÷ start) × 100
The signed result is classified only when the starting value is positive.
Calculators & data
Calculate percentage change without hiding the baseline.
Compare a starting value with a new value, then see the signed relative change, absolute difference, and substituted formula. Zero and negative starting values stay visible instead of being turned into a misleading percentage.
- Runs in your browser
- Formula shown
- Display rounding disclosed
- No signup required
Step 1 · Enter the two values
Set the baseline and outcome.
This calculation runs in your browser. Plainview Tools does not upload, store, or send the values you enter.
Step 2 · Review the calculation
Percentage change
Calculation complete. +25.00%. Increase. Absolute change +20.00.
Relative percentage change
+25.00%
Increase compared with the positive starting baseline.
- Starting value
- 80.00
- New value
- 100.00
- Absolute change
- +20.00
Formula with your values
((new value − starting value) ÷ starting value) × 100
((100 − 80) ÷ 80) × 100 = 25%Unrounded relative result: 25%. Displayed to 2 decimal places.
Read the denominator with the result.
This is percentage change from the starting value. It is not symmetric percentage difference, a score, or a forecast.
What is being calculated
One baseline, two kinds of change.
Relative percentage change compares the difference with the starting value. Absolute change simply subtracts the start from the new value. Plainview Tools keeps both visible so the percentage never loses its denominator.
new − start
This remains available when relative percentage change is undefined or withheld.
When the entered values are percentages, their simple difference can also be shown separately.
Baseline boundaries
A zero baseline makes the conventional formula undefined. A negative baseline can make ordinary increase and decrease language counterintuitive, so the tool explains the boundary rather than inventing a result.
Rounding changes the display only, not the underlying calculation.
Formula reference
A familiar formula with explicit limits.
Reviewed August 24, 2026. The references document the conventional formula and distinguish relative change from percentage-point change. Plainview Tools adds bounded input, display-rounding disclosure, and explicit zero- and negative-baseline handling.