Four clear steps
How to work out a percentage increase
Suppose a value rises from 80 to 100. Label 80 as the original value and 100 as the new value.
- 1Find the increase
100 - 80 = 20.
- 2Divide by the original value
20 / 80 = 0.25.
- 3Multiply by 100
0.25 x 100 = 25%.
- 4State the direction
The percentage increase from 80 to 100 is 25%.
Worked example
Percentage increase from 104 to 125
The increase is 21. Divide that increase by the original value of 104, then multiply by 100.
((125 - 104) / 104) x 100 = 20.19%The unrounded result is approximately 20.1923%. Keeping the full decimal until the final step gives a more accurate answer than rounding halfway through.
Percentage improvement uses the same method when a higher result represents progress: subtract the original result, divide by that original result, and multiply by 100.
Reference examples
Common percentage increase calculations
Each row uses the original value as the denominator, even when the increase itself is the same size.
| Original | New | Increase | Working | Answer |
|---|---|---|---|---|
| 80 | 100 | 20 | (20 / 80) x 100 | 25% |
| 40 | 50 | 10 | (10 / 40) x 100 | 25% |
| 250 | 300 | 50 | (50 / 250) x 100 | 20% |
| 104 | 125 | 21 | (21 / 104) x 100 | 20.19% |
| 1,200 | 1,500 | 300 | (300 / 1,200) x 100 | 25% |
A related question
How to increase a number by a percentage
Finding the percentage increase between two known values is different from increasing one value by a known percentage. To increase 80 by 25%, multiply 80 by 1.25.
80 x (1 + 25 / 100) = 100The multiplier 1.25 contains the original 100% plus the extra 25%. For mixed percentage tasks, use thepercentage calculator or read the broader guide tocalculate percentages.
Decimals and edge cases
What to do with awkward percentage increases
Decimal results
Round only the final result. Two decimal places are usually enough for everyday comparisons.
More than 100%
A value rising from 50 to 125 increased by 150%. Results above 100% are valid.
Starting from zero
The standard formula is undefined because it would divide by zero. Report the absolute increase instead.
A lower new value
That is a decrease, not an increase. Use percentage change to preserve the direction.
Check your working
Common percentage increase mistakes
Dividing by the new value
Percentage increase measures growth against where you started. Divide by the original value, not the new value.
Using the difference as the final percentage
The difference is an amount, not yet a percentage. Divide it by the original value and multiply by 100.
Reversing the old and new values
Label the original value before calculating. Reversing the values changes both the direction and the percentage.
Assuming equal rises and falls cancel out
A 20% rise followed by a 20% fall ends below the starting value because the second percentage uses a different base.
Rounding too early
Keep the full decimal through the calculation and round only the final percentage.
Check your result
Calculate percentage increase online
Enter the original and new values to see the answer, difference, formula, and working together.
Open the percentage increase calculatorFAQ
Percentage increase questions, answered
How do you calculate percentage increase?
Subtract the original value from the new value, divide the increase by the original value, then multiply by 100.
What is the percentage increase formula?
The formula is ((new value - original value) / original value) x 100.
What is the percentage increase from 80 to 100?
The increase is 20. Divide 20 by the original value of 80 and multiply by 100 to get a 25% increase.
Can a percentage increase be more than 100%?
Yes. An increase greater than the entire original value is more than 100%. For example, increasing from 50 to 125 is a 150% increase.
Can you calculate percentage increase from zero?
No finite percentage increase can be calculated from an original value of zero because the formula would require division by zero. State the absolute increase instead.
Is percentage increase the same as percentage difference?
No. Percentage increase uses the original value as the base. Percentage difference compares two values using their average as the base.