Inches to fraction converter

What does this inches to fraction converter do?

This tool takes a length given in decimal inches and rewrites it the way a ruler, tape measure, or machinist’s scale actually reads: as a whole number of inches plus a simple fraction. Rather than leaving you with an awkward figure such as 2.375 in, it returns the familiar 2 3/8 in.

The key choice is the denominator you round to. Tape measures are usually marked in sixteenths, while finer work in a machine shop may call for thirty-seconds, sixty-fourths, or even one-hundred-twenty-eighths of an inch. You pick the smallest division you can read, and the converter snaps the decimal to the nearest mark on that scale.

How the conversion works

A decimal inch value cannot always be written exactly as a fraction with a fixed denominator, so the converter rounds to the nearest available division. The steps are:

1. Multiply the decimal value by the chosen denominator (for example 16 for sixteenths).
2. Round that product to the nearest whole number. This is the total count of fractional units.
3. Split the count into whole inches and a leftover numerator.
4. Reduce the leftover fraction to its simplest form by dividing the numerator and denominator by their greatest common divisor.

The converter fills in the result the moment you type a value and chooses a denominator, and it leaves the output blank until you do.

Formula

To round a decimal value $d$ to the nearest fraction with denominator $D$, first find the total number of fractional units:

Then separate the whole and fractional parts:

where $w$ is the whole inches and $n / D$ is the fractional part. Finally, reduce $n / D$ by their greatest common divisor $g = \gcd(n, D)$:

Step-by-step calculation

1. Enter your measurement in decimal inches.
2. Choose the smallest division you want to round to (1/16 is the default).
3. Read off the whole inches, the numerator, and the reduced denominator.
4. Combine them as “whole numerator/denominator” to get the ruler-ready value.

Examples

Example 1

Convert 2.375 in to a fraction, rounding to the nearest 1/16.

The fraction 6/16 reduces to 3/8, so 2.375 in is 2 3/8 in.

Example 2

Convert 0.5 in to a fraction at 1/16.

The fraction 8/16 reduces to 1/2, so 0.5 in is exactly 1/2 in.

Example 3

Convert 0.1 in to the nearest 1/32.

The fraction 3/32 is already in lowest terms, so 0.1 in is about 3/32 in on a thirty-second scale.

Conversion chart

The table below shows common decimal inch values rounded to the nearest 1/16.

Use this chart as a quick lookup for the values that come up most often when reading a tape measure.

Why round to a denominator

A measuring tool can only show the marks etched on it. A standard tape measure has lines every 1/16 in, so any reading must land on one of those lines. By rounding the decimal to the nearest sixteenth (or finer division on precision tools), the converter gives you a value you can actually mark and cut, instead of a decimal that no ruler displays.

Choosing a larger denominator (1/64 or 1/128) gives a closer match to the original decimal but a busier fraction; a smaller denominator (1/8 or 1/4) is easier to read but less precise. Pick the division that matches your tool and your tolerance.

Frequently asked questions

What is 2.375 inches as a fraction?

Rounded to the nearest 1/16, 2.375 in equals 2 3/8 in. The decimal part 0.375 is exactly 6/16, which reduces to 3/8.

How do I convert a decimal inch to the nearest 1/16?

Multiply the decimal by 16, round to the nearest whole number, then write that count over 16 and reduce. For example, $0.625 \times 16 = 10$, and 10/16 reduces to 5/8.

Why is my fraction reduced to smaller numbers?

The converter always simplifies the fraction so it reads naturally. A value like 6/16 is shown as 3/8 because both share a common factor of 2.

How do I go the other way, from a fraction back to a decimal?

Divide the numerator by the denominator and add the whole part. Our decimal to fraction converter covers the reverse direction in detail.

How many inches are in a foot?

There are 12 inches in a foot. To break a measurement in feet down to inches first, try our feet to inches converter.