Is Percentage Calculator free to use?

Yes. Percentage Calculator is free, has no usage cap and does not require an account. There is no paid tier that unlocks extra output.

Does my data get uploaded to a server?

No. The tool is a JavaScript function that runs inside your browser tab. Nothing you paste or drop in is transmitted, logged or stored by us.

Do I need to create an account?

No account, no email address and no sign-in. Open the page and start working.

Does it work on a phone or tablet?

Yes. The interface is responsive and works in mobile Chrome, Safari, Edge, Firefox and Samsung Internet. You can also install Toolspea as an app from the browser menu.

Can I use the output commercially?

Yes. You keep every right you already had over the input, and we claim nothing over the output.

What is the difference between percentage change and percentage points?

If a rate moves from 4% to 5%, that is a rise of one percentage point but a 25% relative increase. Mixing them up is the most common reporting mistake.

Why is an increase then an equal decrease not back to the start?

Because each is applied to a different base. Add 20% to 100 and you get 120; take 20% off 120 and you get 96, since the second calculation works from the larger number.

How do I reverse a discount to find the original price?

Divide the discounted price by one minus the discount rate. £80 after 20% off is 80 ÷ 0.8 = £100.

Calculators

Percentage Calculator

Percentages, increases, decreases and differences with the working shown.

First number

Result

Options

Calculation

Second number

Decimal places

Everything above is processed in this browser tab. Your input is never sent to a server.

What is Percentage Calculator?

Percentage Calculator answers the four percentage questions people actually need: what is X percent of Y, what percentage is X of Y, what is the value after an increase or decrease, and what is the percentage change between two numbers. Each answer shows the formula used.

How to use it

1Enter the first number.
2Choose which of the five calculations you need.
3Enter the second number.
4Read the answer and the formula used to produce it.

Features

Five distinct percentage operations rather than one ambiguous box
The formula is printed with the result so it can be checked
Configurable decimal precision

When people use it

Applying a discount

Decrease mode gives both the final price and the amount saved, which is the number a customer usually wants to see.

Reporting a change

Percentage change from last month to this month, with the sign, avoids the classic error of dividing by the wrong baseline.