The method
How it is worked out
Percentage = part ÷ whole × 100; change = (new − old) ÷ old × 100
- part
- The part or first value
- whole
- The whole or comparison value
Percentage Calculator
Calculate a percentage of a number, the percentage one value is of another, or the percentage change between two values. The result updates as you type so you can compare scenarios quickly.
Keep in mind
What it leaves out
- Zero basesPercentage change is undefined when the starting value is zero.
- ContextA percentage alone does not explain why values changed.
- RoundingDisplayed results may be rounded.
Use the calculator to compare scenarios rather than as a guaranteed forecast.
About the Percentage Calculator
Use the Percentage Calculator for everyday comparisons such as a discount, the share of a total or a change between two values. Select the calculation you need and enter the numbers that belong in its part, whole or original and new value fields.
How it works and an example to tryShow less
How to use the result
A percentage of a number multiplies the total by the percentage divided by 100. The percentage that a part represents divides the part by the whole; percentage change divides the difference between new and old values by the old value. A zero denominator cannot define a meaningful percentage change, and rounding can alter the displayed last decimal.
Example to try
Work out 15% of 64, then calculate what percentage a smaller amount is of 64. For growth, compare a starting value with a new value and reverse them: a fall and the equal-sized recovery do not usually have the same percentage.
Put it to work
Try it on a real situation
Load an example
What moves the result most
Worked out from your figures above. Tap a row to try it.
Who uses it, and when
Shoppers checking a discount, students and analysts working with growth figures, small-business owners calculating a share of sales, and anyone who wants to be sure a percentage change is quoted the right way round.
Mistakes worth avoiding
- Adding percentage points when the question is about percentage change.
- Assuming a 20% fall followed by a 20% rise gets you back to where you started.
- Quoting a huge percentage change from a tiny starting number as if it were meaningful.
Questions
What does the Percentage Calculator do?
Calculate a percentage of a number, the percentage one value is of another, or the percentage change between two values.
How should I use the result?
A percentage of a number multiplies the total by the percentage divided by 100. The percentage that a part represents divides the part by the whole; percentage change divides the difference between new and old values by the old value. A zero denominator cannot define a meaningful percentage change, and rounding can alter the displayed last decimal.
Does TechBullion store the information I enter?
The core calculation or transformation runs in your browser. Normal website security and analytics may still record page-level events, but the tool does not need to create a public record from your inputs.
What mistakes do people make with a percentage calculator?
Adding percentage points when the question is about percentage change. Assuming a 20% fall followed by a 20% rise gets you back to where you started. Quoting a huge percentage change from a tiny starting number as if it were meaningful.
Is the result guaranteed?
No. Use the result as a practical check or planning aid and verify important decisions with the relevant primary source, provider or professional advice.
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Calculator results are estimates based on the figures entered and are not financial, investment, legal or tax advice.