Percentage Calculator
Percentage Calculator is a free finance tool that runs directly in your browser with no account required.
About this tool
A quick three-mode percentage tool: find what X% of a value is, increase a value by a percentage, or decrease it by a percentage. Each mode shows the original value, the change amount, and the resulting total so you can see the arithmetic at a glance.
How to use
- Enter the base number in Value.
- Enter the percentage in Percent.
- Pick a Mode: "What is X% of Y?", "Increase by X%", or "Decrease by X%".
- Read the result, the change amount, and the total from the metrics panel.
Frequently asked questions
What does each mode calculate?
"What is X% of Y?" returns Value times Percent/100; "Increase by X%" returns Value times (1 + Percent/100); "Decrease by X%" returns Value times (1 - Percent/100).
Can I use percentages over 100 or negative values?
Yes. A 150% increase or a negative value computes normally — the formulas are applied directly without artificial caps.
Why are results formatted like currency?
Outputs are shown to two decimal places in a money-style format because price and budget questions are the most common use, but the math works for any quantity.
How do I reverse a percentage change?
Note that increases and decreases are not symmetric: after a 20% decrease you need a 25% increase to get back to the original, because the second change applies to a smaller base.
Is anything I type stored or transmitted?
No. The calculation runs instantly in your browser and nothing is saved or uploaded.