Fraction ↔ Decimal ↔ Percent Converter

About this tool

Type a value into any one of the three fields — fraction, decimal, or percent — and the other two update instantly, with the fraction reduced to lowest terms. It's the quick way to move between the forms a number can take: 3/4, 0.75, and 75% are all the same value.

Fraction to decimal: divide the numerator by the denominator. 3 ÷ 4 = 0.75. Some fractions divide evenly; others repeat forever (1/3 = 0.333…, 2/7 = 0.285714…) and are shown rounded.

Decimal to percent: multiply by 100. 0.75 → 75%. Percent to decimal: divide by 100. This is the same "move the decimal two places" rule from the percentages guide.

Decimal to fraction: write the digits over the matching power of ten and simplify. 0.75 = 75/100, and dividing top and bottom by their greatest common divisor (25) gives 3/4. That GCD step is what "lowest terms" means — 6/8, 9/12, and 75/100 all reduce to 3/4.

Worked examples.

Improper fractions and mixed numbers. A fraction over 1 (like 5/4) converts to a decimal above 1 and a percent above 100%. As a mixed number that's 1¼. This tool works in improper-fraction form.

Repeating decimals aren't exact. 1/3 can't be written exactly as a decimal, so 0.3333 shown here is rounded. Converting that rounded decimal back to a fraction may give 3333/10000 rather than 1/3 — start from the fraction when you need the exact value.

Zero denominator is undefined and rejected. A fraction like 4/0 has no value.

For percentage calculations beyond conversion — a percentage of a number, an increase or decrease — use the percentage calculator. To reduce a fraction or find a common denominator via factors, the GCD & LCM calculator.

Frequently asked questions

How is the fraction simplified?

By dividing the numerator and denominator by their greatest common divisor. 6/8 ÷ 2 = 3/4; 75/100 ÷ 25 = 3/4.

What happens with repeating decimals?

They're shown rounded to a sensible number of places — 1/3 as 0.3333 — because a repeating decimal can't be written out in full. The fraction form is the exact one.

Can the denominator be zero?

No. Division by zero is undefined, so a zero denominator is treated as invalid.

How do I convert a decimal like 0.375 to a fraction by hand?

Put the digits over the matching power of ten (375/1000) and divide both by their GCD (125) to get 3/8.

What about a percent over 100, like 150%?

It's a value greater than 1: 150% = 1.5 = 3/2. The tool handles improper fractions and percentages above 100.

Why did converting a decimal back to a fraction not give me what I started with?

If the decimal was a rounded repeating value, the reverse conversion works from the rounded number. Enter the fraction directly to keep it exact.