La Fonction

Decimal to percentage calculator

A decimal becomes a percentage when you multiply it by 100, which is the same as sliding the point two places to the right. The boxes above do it in either direction.

12 × 12 = 144

Adding 12 to itself 12 times gives the same answer.

Both directions in one line

Decimal to percentage: × 100. 0.375 becomes 37.5%. Percentage to decimal: ÷ 100. 37.5% becomes 0.375. Nothing else changes, and the two are the same quantity written two ways.

Decimal Percentage
0.01 1%
0.05 5%
0.125 12.5%
0.25 25%
0.5 50%
0.75 75%
1 100%
1.4 140%

Above 100% is not an error

Any decimal larger than 1 converts to more than 100%. A growth factor of 1.4 is 140% of the starting figure, which is a 40% increase — the percentage of the total and the percentage of change are different questions, and mixing them is where most confusion starts.

Starting from a fraction

Divide the top by the bottom to get the decimal, then multiply by 100. 3/8 is 3 ÷ 8 = 0.375, so 37.5%. Do the division first every time; there is no shortcut that skips it.

When the answer looks wrong

  • Off by a factor of 100. You converted in the direction you did not intend. 0.5 is 50%, while 50 is 5000%.
  • A percentage that was already a percentage. Multiplying 37.5% by 100 again gives 3750%.
  • Rounding too early. Convert first, round last, especially with repeating decimals: 1/3 is 33.33%, not 33%.

For the keystrokes behind each of these, see how to find a percentage on a calculator. To undo a percentage change rather than convert one, use the reverse percentage calculator, or browse the calculators.