Millimeters to Fractional Inches

Convert Millimeters to Fractional Inches

"Millimeters to Fractional Inches" Calculator

How to Convert Millimeters to Fractional Inches

Millimeters to Fractional Inches Conversion Formula

To convert millimeters to fractional inches (SAE), use this precise formula:

inches = millimeters ÷ 25.4
Then find the closest fraction with denominator up to 64

Step-by-Step Conversion Guide

Take your measurement in millimeters (e.g., 20.6375 mm)
Divide by 25.4 (20.6375 ÷ 25.4 = 0.8125")
Find the nearest fraction (0.8125 = 13/16")
Get your result in fractional inches

Common Millimeters to SAE Fractions

Millimeters	SAE Fraction	Decimal Inches
5 mm	13/64"	0.1969"
6 mm	15/64"	0.2362"
8 mm	5/16"	0.3150"
10 mm	25/64"	0.3937"
12 mm	15/32"	0.4724"
13 mm	33/64"	0.5118"
15 mm	19/32"	0.5906"
19 mm	3/4"	0.7480"

Practical Applications of Metric to SAE Converter

Automotive Repair: Finding SAE wrenches for metric bolts
Metalworking: Converting sizes for American tools
International Trade: Adapting sizes for different markets
Manufacturing: Working with imported equipment
Drilling: Finding closest drill bit size

Finding Closest Fraction Examples

Converting 17 mm:

17 ÷ 25.4 = 0.6693"
Closest fraction: 43/64" (0.6719")
Difference: only 0.0026" (0.066 mm)

Fraction Finding Algorithm

The calculator uses continued fractions method to find the best approximation with denominator limited to 64. This ensures maximum accuracy while maintaining SAE standards compatibility.

Conversion Accuracy

The calculator shows both fractional and decimal values so you can evaluate the approximation accuracy. For most practical applications, the error is less than 0.1 mm.