CAGR Calculator
Calculate compound annual growth rate from a starting value, ending value, and time in years.
Open toolPercent Change Calculator
Calculate percentage change from a positive starting value to a new value. Review the absolute difference and whether the change is an increase or decrease.
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How Percent Change Calculator works
The value difference is expressed relative to the positive starting amount.
The starting value is subtracted from the new value. Dividing that difference by the starting value and multiplying by one hundred gives percentage change. The difference also determines the displayed direction.
The starting value must be greater than zero. Zero or negative bases need a different comparison convention.
How to use Percent Change Calculator
The starting value sets the percentage basis, so the input order matters.
Enter values in their intended order
Enter a positive starting value and a nonnegative new value. Keep their unit and basis consistent. The starting value is the denominator, so reversing the inputs generally changes the percentage even when the absolute movement is the same.
Starting value
Calculate the percentage change
Select Calculate and read the signed percentage change. The page subtracts the starting value from the new value, then relates that difference to the starting amount. A decrease gives a negative percentage under this positive-base convention.
-50%
Review the difference and direction
Read Absolute difference and Direction with the percentage. Record the starting amount when sharing the result so another person can reproduce its basis. Zero or negative starting values need a different comparison convention and are not accepted here.
Absolute difference
Comparisons that use a positive baseline
Use the same measurement basis and keep the order of the two values explicit.
Describe an increase
A hypothetical change from eighty to one hundred is an increase of twenty units and twenty five percent. The starting eighty is the percentage basis. This example makes the absolute and relative measures visible without assigning a currency or subject to the numbers.
Describe the reverse change
Reversing that example from one hundred to eighty gives a twenty percent decrease. The absolute difference has the same magnitude, but the percentage base is different. This helps explain why a rise and its reversal need not have equal percentages.
Compare two measurements consistently
Enter a before and after value measured on the same basis, then preserve the unit and dates outside the form. The tool does not discover whether two totals describe the same population or period, so that context needs checking separately.
Relative change and percentage points
Read the signed percentage with its original baseline and absolute difference.
The absolute difference uses the same unit as the inputs. The main percentage divides that difference by the starting value. Direction describes whether the new value increased, decreased or stayed the same.
If the inputs are themselves percentages, their absolute difference can describe percentage points. The main output still describes relative change. Retain the labels rather than presenting those two measures as interchangeable quantities.
Check the baseline and measurement units
Check value order and a positive base before comparing changes.
The starting value must be positive. For a comparison that begins at zero, this calculator cannot supply a meaningful finite relative percentage. Record the absolute change separately instead of changing the baseline to satisfy the form.
The page does not adjust for inflation, elapsed time or changes in the quantity being measured. For an annualized endpoint rate, CAGR Calculator adds a duration input; use it only when that comparison matches the available values.
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Open toolPercent Change Calculator: common questions
Answers about using Percent Change Calculator and understanding its results.
What does a negative result mean?
The new value is lower than the starting value.
Why can't I start from zero?
The percentage formula divides by the starting value, so a zero base is undefined.
Are a rise and its reverse fall the same percentage?
Usually not. Reversing the values changes the denominator. Keep the starting and new value in the intended order.
Can I compare against a negative starting value?
No. This form requires a positive starting value and a nonnegative new value. Another comparison convention is needed outside those inputs.
Use Percent Change Calculator
Calculate percentage change from a positive starting value to a new value.