Percentage Calculator: Find a Percent, Increase or Difference
Percentage calculations appear in discounts, comparisons, reports and everyday budgeting. Choose the calculation type that matches your question, enter the values and verify the result context.
Choose the percentage calculation
- To find a percentage of a number, fill What is this percentage? and Of which number?
- To find the change between two values, fill Starting value and New value.
- Choose Calculate and read the result.
- Check which value is the original and which is the new one.
- Confirm taxes, fees and rounding separately when the result is used for money.
Three common percentage questions
The tool answers two questions: what is a given percentage of a number, and what is the percentage change from a starting value to a new value. The question of what share one number is of another is answered by dividing the part by the whole and multiplying by 100.
Select the correct baseline
Percentage increase and decrease depend on the original value used as the denominator. Reversing the baseline can produce a different percentage.
Two calculations in one tool
Fill What is this percentage? and Of which number? to find a percentage of a number, for example 15 percent of 80. Fill Starting value and New value to find the percentage change from one number to the other. You can use either part alone, and then press Calculate. To find what share one number is of another, divide the part by the whole and multiply by 100, so 20 out of 80 is 25 percent.
Worked examples
Fifteen percent of 80 is 12. A change from 80 to 100 is an increase of 25 percent. A change from 100 to 80 is a decrease of 20 percent. Adding 15 percent VAT to a price of 200 means 15 percent of 200, which is 30, so the price with VAT is 230. Check which number is the starting value, because that decides the result.
Why the direction matters
A rise of 25 percent followed by a fall of 25 percent does not bring you back to the start, because each percentage uses a different starting value. It is also important to separate percent from percentage points: if an interest rate goes from 5 percent to 7 percent, it has risen by 2 percentage points but by 40 percent.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example 15% of 200 is 200 x 15 / 100 = 30.
How do I calculate percentage increase?
Subtract the original value from the new value, divide by the original value and multiply by 100.
Is percentage change symmetric?
No. Increasing from one baseline to another and then reversing the comparison can produce different percentage changes.
How do I find a percentage of a number?
Multiply the number by the percentage and divide by 100. For 15 percent of 200 that is 30.
How do I find a percentage change?
Subtract the starting value from the new value, divide by the starting value and multiply by 100.
Why is the change from 100 to 80 not 25 percent?
Because the starting value is now 100. A fall of 20 is 20 percent of 100.
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