Home › Math & Science › Decimal to Percent Calculator
Decimal to Percent Calculator
Use this free decimal to percent calculator to convert decimals to percent, percent back to decimal, and fractions to percent — all in one place. Enter a number, pick a mode, and the result updates instantly, with a visual percent bar that shows exactly where your value sits between 0% and 100%.
Enter a decimal between 0 and 1 for a percent under 100% — values above 1 give percents above 100%, which is fine for growth and increases. You can also type a trailing % sign; it is ignored in this mode.
How decimal to percent conversion works
A decimal and a percent are two ways of writing the same amount. The word percent means "out of one hundred," so a percent is simply a number of hundredths. The decimal 0.75 means 75 hundredths, and 75 hundredths out of 100 is 75%. That is the whole idea behind the conversion: to turn a decimal into a percent, multiply by 100; to turn a percent into a decimal, divide by 100.
Decimal = Percent ÷ 100
Percent = (Numerator ÷ Denominator) × 100
Moving the decimal point is the fastest way to do it by hand. Multiplying by 100 moves the point two places to the right, so 0.75 becomes 75, and adding the percent sign gives 75%. Dividing by 100 moves the point two places to the left, so 40% becomes 0.40, which is normally written as 0.4. The calculator does the same arithmetic, and the decimal places selector controls how the answer is rounded — 2 places is the usual choice for everyday work, while more places help when the exact value matters, for example in interest rates or measurements.
Fractions fit the same pattern with one extra step. A fraction is a division problem waiting to happen: 1/4 means 1 divided by 4, which is 0.25, and 0.25 × 100 = 25%. In Fraction to Percent mode, enter the numerator (the top number) and the denominator (the bottom number) and the calculator divides first, then multiplies by 100. The same works for improper fractions: 5/4 = 1.25, which is 125%, a percent above 100% that simply means "more than the whole."
Percents above 100% are normal and useful. A decimal of 1.5 means one and a half wholes, so it is 150%. You meet these whenever something grows: a price that doubles has risen by 100%, and a business that triples its sales has grown to 300% of its starting size. The calculator accepts any decimal, including values above 1 and negative values, and the percent bar fills completely once the value passes 100%.
Repeating decimals need a little care. Some fractions never terminate: 1/3 = 0.3333... going on forever, so as a percent it is 33.333...%. No calculator can print an endless string of threes, so the answer is rounded to the number of decimal places you choose. With 2 places, 1/3 becomes 33.33%; with 4 places, 33.3333%. If you are adding percents that came from repeating decimals, keep a few extra places during the work and round only the final answer, or the rounding can add up to a visible error.
Worked example
Convert the decimal 0.75 to a percent, then convert 75% back to a decimal, and convert the fraction 1/4 to a percent.
Step 1: Decimal to percent — 0.75 × 100 = 75, so 0.75 is 75%. The shortcut is to move the decimal point two places right: 0.75 becomes 75.
Step 2: Percent to decimal — 75 ÷ 100 = 0.75, so 75% is 0.75. Move the point two places left and drop the percent sign.
Step 3: Fraction to percent — 1 ÷ 4 = 0.25, then 0.25 × 100 = 25, so 1/4 is 25%.
So the answers are: 0.75 = 75%, 75% = 0.75, and 1/4 = 25%. Try the same numbers in the calculator above — switch modes to check each one — then try 0.125, which is 12.5%, and 2/3, which is 66.67% with 2 decimal places.
FAQ
How do I convert a decimal to a percent?
Multiply the decimal by 100 and add the percent sign. For example, 0.75 × 100 = 75, so 0.75 is 75%. A quick shortcut is to move the decimal point two places to the right: 0.75 becomes 75%.
How do I convert a percent to a decimal?
Divide the percent by 100, or move the decimal point two places to the left and drop the percent sign. For example, 40% becomes 0.40, which is usually written as 0.4. This calculator does it in Percent to Decimal mode.
What is 0.5 as a percent?
0.5 as a percent is 50%. Multiply 0.5 by 100 to get 50, then add the percent sign. Half of anything is 50 out of 100, which is exactly what 50% means.
How do I convert a fraction to a percent?
Divide the numerator by the denominator to get a decimal, then multiply by 100. For example, 1/4 = 0.25, and 0.25 × 100 = 25%. Use the Fraction to Percent mode on this page and enter the numerator and denominator separately.
What about repeating decimals, like 1/3?
Some fractions give repeating decimals: 1/3 = 0.3333... and as a percent that is 33.333...%. The calculator rounds it to the number of decimal places you choose — with 2 places it shows 33.33%. Use more decimal places when you need the extra precision, for example in interest or tax calculations.