What is 0.625 as a fraction?

5/8. Write it as 625/1000, then divide both by their GCD of 125.

Why do I choose the number of decimal digits?

The calculator can't tell whether 0.625 means exactly three digits or a longer number you trimmed. The digit count sets the starting denominator — a 1 followed by that many zeros.

What if my decimal repeats, like 0.333…?

A repeating decimal has an infinite expansion, so this power-of-10 method can only approximate it. 0.3333 gives 3333/10000, close to but not exactly 1/3. Enter the exact fraction if you know it.

Does it always fully simplify?

Yes. It divides top and bottom by their greatest common divisor, so you always get lowest terms — never 4/8 when 1/2 is meant.

What is 0.375 as a fraction?

3/8. 375/1000 with a GCD of 125. It's a common tape-measure and drill-bit value.

How do I convert a decimal like 2.75 with a whole part?

Convert the decimal part (0.75 → 3/4) and keep the whole number: 2 3/4, or as an improper fraction 11/4.

Decimal to Fraction Calculator

Every terminating decimal is a fraction in disguise. 0.5 is 1/2, 0.75 is 3/4, 0.625 is 5/8. The work is knowing how many zeros go in the denominator and how far the fraction reduces — this calculator does both and shows the greatest common divisor it used.

The decimal to fraction method

Write the decimal over , where is the number of digits after the point, then reduce by the greatest common divisor of the numerator and .

Worked example

The calculator’s defaults are 0.625, converted at 3 digits.

Check: .

Decimal to Fraction Calculator worked example diagram — A visual read of the worked example above — the same numbers the calculator returns for its default inputs.

What your results mean

The numerator and denominator are your answer in lowest terms — this is the fraction you’d write on paper. The GCD used to simplify shows exactly what number both the raw numerator (625) and raw denominator (1000) were divided by to get there; if the GCD is 1, the fraction was already in lowest terms before simplifying.

The decimal used field shows the decimal value after rounding to your chosen digit count. If it doesn’t match what you typed, you rounded at fewer digits than your original number had — try a higher digit setting for more precision.

Common decimals and their fractions

Decimal	Fraction	GCD used
0.5	1/2	5
0.25	1/4	25
0.75	3/4	25
0.125	1/8	125
0.375	3/8	125
0.2	1/5	2

Notice the GCD is what does the real work — a decimal like 0.5 (500/1000) needs a GCD of 500 to collapse all the way down to 1/2, while 0.375 only needs 125.

A note on precision

Choosing more decimal digits than your number actually has doesn’t hurt — trailing zeros just get absorbed into the GCD. But choosing fewer digits than you meant will round your input, which matters for anything beyond simple fractions. If you’re working from a measurement, it can help to check the result against the fraction to decimal calculator run in reverse, or compare it to the equivalent fractions calculator to see other fractions that represent the same value.

Decimals with a whole number part

Handle the whole number separately and convert only the decimal part. For 2.75, the decimal part is 0.75:

Whether you write or depends on what you need next. Mixed numbers suit measurements; improper fractions suit further calculations.

Converting a repeating decimal

The digit-count method only works for decimals that end. For one that repeats forever, use algebra. Let . The repeating block has two digits, so multiply by 100:

The pattern is worth remembering: a single repeating digit goes over 9 (), and two repeating digits go over 99.

Reading the place value aloud

A shortcut that needs no formula: say the decimal using its place value name, and the fraction writes itself. 0.35 is “thirty-five hundredths”, so it’s , which simplifies to . 0.008 is “eight thousandths”, or .

Common mistakes

Wrong power of 10. 0.06 has two decimal places, so it’s , not . Count digits after the point, including zeros.
Not simplifying. is correct but unfinished. Divide by the GCD to reach .
Treating a rounded decimal as exact. 0.33 is , not . If the decimal really repeats, use the repeating method above.
Losing the whole number. 3.2 is , not .

Decimal inches to a ruler fraction

Machinists and CAD drawings give decimals; tape measures show sixteenths. 0.4375 inch is , which simplifies (GCD 625) to . A faster route for inches is to multiply by 16: , so it’s 7/16. The inches to fraction calculator rounds to the nearest mark when the decimal doesn’t land exactly.

Decimals that repeat after a delay

In 0.1666…, only the 6 repeats. Multiply to line up the repeating parts, then subtract:

Try these

Decimal	Fraction
0.45	9/20
0.125	1/8
1.6	1 3/5
0.0625	1/16
0.36	9/25

About the formula: The decimal is first written as a fraction over a power of 10 (0.625 = 625/1000), then both numbers are divided by their greatest common divisor to reach lowest terms.