Useful Utilities

Percentage Calculator

Percent of a number, one number as a percent of another, and percent change between two values, with every formula spelled out.

Fill in the values and calculate

Question to answer*
First number (A)*
Second number (B)*
Decimal placesHow many decimals the results keepDefault 2

The form sends itself back to this page — results print below, computed on the server.

No results yet: fill the form above and press Calculate.

About Percentage Calculator

The three questions percentages get used for in everyday life: an amount at a given rate, one number's share of another, and the move between an old value and a new one.

Every answer also prints the reading on the other side of it, so a discount figure and the markup that would reverse it can be compared on the same screen.

Questions about Percentage Calculator

Is percent change the same as percent difference?

No. Percent change measures one move from a starting value; a symmetric percent difference would divide by the average of the two values instead.

Why does the change mode refuse a starting zero?

Percent change divides the move by the starting value, and anything over zero is undefined. State the move in absolute terms instead.

How do I get a price with tax added on?

Use the percent-of mode and read the plus row: B x (1 + A%) raises B by A percent in one step.

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