Percentage Change Calculator
Calculate the starting value, final value, and percentage change directly in your browser. Increases, decreases, and reverse calculations work without switching modes.
Starting value, final value, and change
Edit any two fields. The third is calculated automatically.
The two most recently edited fields remain inputs.
Enter any two of the three values.
Swap is only available when starting and final values are greater than 0.
Change
Ratio and reverse change
Good to know
Good to know
The percentage change calculator calculates directed changes from a positive starting value directly in your browser, using the formula r = ((final value − initial value) / initial value) × 100. Enter two of the three values — initial value, final value, percentage change — to calculate the third.
Typical searches include calculate percentage change, percentage increase, and percentage decrease. Calculation runs locally in the browser. Important: this calculator handles directed changes from a positive starting value — percentage difference, percentage points, discounts, and VAT are separate concepts and not part of this tool.
Typical use cases
Calculate a missing value from two known ones
Enter two of the three values — initial value, final value, or percentage change — to calculate the missing third value directly.
Determine the reverse change back to the original value
Calculate by what percentage an already changed value would need to decrease or increase again to return to the original starting value — this is not simply the negative of the original rate.
Swap initial and final value for the next comparison
Swap the initial and final value to quickly view the change in the opposite direction, provided both values are greater than 0.
Tips for better results
Don't confuse with percentage points or discounts
Percentage difference between two values regardless of direction, percentage points, discounts, and VAT are separate questions with different formulas than a directed change.
Don't equate the reverse change with the negative original rate
A 25% increase is not undone by a 25% decrease — the reverse change is based on the new, higher value and is therefore smaller.
How it works
How it works
Step by step
Features
Features
Calculate any of the three values
Enter two of initial value, final value, and percentage change; the third is calculated automatically.
Calculate the reverse change
Determines the percentage change that leads from the changed value back to the original starting value.
Calculation path and formula shown
The formula and calculation path are shown transparently and can be copied.
Frequently asked questions
Frequently asked questions
What's the difference from a percentage difference?
This calculator handles a directed change from a fixed starting value; percentage difference between two values is independent of direction and a separate question.
Why must the initial value be greater than 0?
With a starting value of 0, relative percentage change is mathematically undefined, since it would divide by zero.
Are my inputs uploaded?
No. Calculation runs entirely locally in the browser.
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