Percentage change calculator
Enter a starting and ending value to get the percentage change, the absolute difference, and the multiplier — for tracking metric movements like month-over-month growth or a change in CTR.
Increase of 25.00%.
- Change
- +25.00%
- Absolute difference
- +300.00
- Multiplier
- 1.25×
Percent change = (new − old) ÷ |old| × 100. A drop from 100 to 0 is −100%; a rise from 0 cannot be expressed as a percentage.
How it works
Percentage change is the new value minus the old value, divided by the absolute value of the old value, times 100. It converts a raw movement into a comparable rate: a 300-unit rise means something very different on a base of 1,000 than on a base of 100,000.
The tool also shows the absolute difference and the multiplier (new divided by old), because different situations call for different framings — 'up 25%', 'up 300 units', and '1.25×' all describe the same move and each lands differently in a report.
It runs entirely in your browser. One edge case matters: percentage change from a starting value of zero is undefined, because any increase from nothing is infinite in percentage terms — use the absolute difference there instead.
Assumptions and limitations
- Percentage change from zero is mathematically undefined, and changes across a sign (negative to positive) produce figures that are technically correct but easy to misread.
- A percentage change compresses two numbers into one and hides the base. Always report the underlying values alongside it, especially for small denominators where large percentages can be trivial in absolute terms.
- Chaining percentage changes is not additive — a 50% rise followed by a 50% fall does not return to the start. Recompute from the actual values rather than adding percentages.
Frequently asked questions
How do I calculate percentage change?
Subtract the old value from the new value, divide by the absolute value of the old value, and multiply by 100. Going from 1,200 to 1,500 is (1,500 − 1,200) ÷ 1,200 × 100 = 25%. A negative result is a decrease.
What is the difference between percentage change and percentage points?
Percentage change is relative: moving from a 4% rate to a 5% rate is a 25% increase. Percentage points are absolute: that same move is a 1 percentage-point increase. Confusing the two is a common reporting error, especially with rates like CTR or conversion rate.
Why can't I calculate percentage change from zero?
Because dividing by zero is undefined — any increase from a base of nothing is infinite in percentage terms. When the starting value is zero, report the absolute difference instead, which this tool still shows.
How do I calculate month-over-month or year-over-year growth?
Use the same formula with the earlier period as the starting value and the later period as the ending value. This calculator gives you the percentage, the absolute change, and the multiplier for exactly that comparison.
Is anything I enter here stored?
No. The calculation runs entirely in your browser and nothing you type is transmitted or saved.
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