Everyday mathematics

Percentage calculator

Find a percentage, compare two values, or work backwards from a final amount. See the answer, a visual comparison and the calculation steps.

instant results · worked formulas

Find a share

What is a percentage of a number?

Calculated part

Compare the values

Bar lengths show relative magnitudes; the numbers retain their signs.

Calculation steps

Formula

With your numbers

Displayed numbers may be rounded; calculations use full precision.

Find the percentage

One value is what percentage of another?

Percentage of the whole

Compare the values

Bar lengths show relative magnitudes; the numbers retain their signs.

Calculation steps

Formula

With your numbers

Displayed numbers may be rounded; calculations use full precision.

Compare values

How much did a value rise or fall?

Relative change

Compare the values

Bar lengths show relative magnitudes; the numbers retain their signs.

Calculation steps

Formula

With your numbers

Displayed numbers may be rounded; calculations use full precision.

Find the original

Work backwards from a final value.

Original value

Compare the values

Bar lengths show relative magnitudes; the numbers retain their signs.

Calculation steps

Formula

With your numbers

Displayed numbers may be rounded; calculations use full precision.

Find the whole

If a part is a known percentage, what is the whole?

Whole or reference amount

Compare the values

Bar lengths show relative magnitudes; the numbers retain their signs.

Calculation steps

Formula

With your numbers

Displayed numbers may be rounded; calculations use full precision.

Increase or decrease a value

Apply a signed percentage change to a starting value.

Final value

Compare the values

Bar lengths show relative magnitudes; the numbers retain their signs.

Calculation steps

Formula

With your numbers

Displayed numbers may be rounded; calculations use full precision.

Successive percentage changes

Apply two changes in order; their percentages do not simply add.

Final value

Compare the values

Bar lengths show relative magnitudes; the numbers retain their signs.

Calculation steps

Formula

With your numbers

Displayed numbers may be rounded; calculations use full precision.

Choose the right percentage calculation

A percentage of an amount

For 15% of 80, multiply 80 by 15 and divide by 100. The answer is 12.

What percentage is this part?

For 12 out of 80, divide 12 by 80 and multiply by 100. The answer is 15%.

Increase or decrease

From 80 to 100, the difference is 20 and the relative increase is 25% of the starting value.

Find the original amount

If the final value is 120 after a 20% increase, divide 120 by 1.2. The original was 100.

Percentage points are not percent change

A rise from 20% to 25% is 5 percentage points, but a 25% relative increase. Select the percentage-values option to see both.

Zero and negative values

A zero starting value makes relative percentage change undefined. Negative starting values need an explicit convention; here the denominator is the absolute starting magnitude. Absolute differences remain available.

Related everyday calculators

For a full price breakdown, use these dedicated tools.

Frequently asked questions

How do I find 15% of 80?

Multiply 80 by 15 and divide by 100. The result is 12.

How do I calculate a percentage increase?

Subtract the starting value from the final value, divide by the starting magnitude, and multiply by 100. For a positive starting value, this is the usual percent-change formula.

What is the difference between percent and percentage points?

Moving from 20% to 25% is an increase of 5 percentage points. Relative to 20%, it is a 25% increase.

Can I calculate a percentage change from zero?

No finite relative percentage change exists when the starting value is zero. You can still calculate the absolute difference.

How do I reverse a percentage change?

Divide the final value by one plus the signed percentage change divided by 100. A −100% change does not give a unique original value.