1/2" To Mm - SAE To Metric Calculator

Do you need to convert 1/2 inch to mm?

1/2 inch = 12.7 mm

If you're curious how we got that answer, here's the 1/2" to mm formula:

1 ÷ 2 × 25.4 = 12.7 mm0.5 × 25.4 = 12.7 mm

To convert 1/2 inch to mm, divide 1 by 2 to convert the fraction to a decimal. Then, multiply that by 25.4 since there are 25.4 millimeters in one inch.

That's the formula that our calculator uses to find that 1/2 inch to millimeters is 12.7 mm.

Convert a measurement from SAE to metric or metric to standard SAE using the calculator below. Learn more about SAE and metric measurements, and refer to the conversion chart below.

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Result: Metric Measurement

Result: Metric Measurement mm Result: SAE Measurement

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On this page:

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• Calculator
• How to Convert SAE to Metric
• Step One: Convert the Inch Fraction to an Inch Decimal
• Step Two: Convert the Inch Decimal to Millimeters
• SAE to Metric Conversion Chart
• More Standard to Metric Conversions
• References

Person Icon By Joe Sexton

Joe is the creator of Inch Calculator and has over 20 years of experience in engineering and construction. He holds several degrees and certifications.

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Stephen specializes in all aspects of the automotive world and has been an automotive enthusiast since childhood. He follows the global automotive industry closely, with an eye on the latest vehicle technologies.

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Sexton, J. (n.d.). 1/2" to mm - SAE to Metric Calculator. Inch Calculator. Retrieved December 9, 2025, from https://www.inchcalculator.com/sae-to-metric-calculator/

How to Convert SAE to Metric

SAE, or standard, and metric sockets, wrenches, and fasteners are both commonly used, but the difference between them is significant. Before we explain how to convert SAE to metric, it’s important to understand what these terms actually mean.

SAE stands for Society of Automotive Engineers,[1] and is based on standard imperial and U.S. customary measurement systems. It uses measurements in inch fractions and is most commonly used in the United States.

The metric system was developed more recently and is commonly used worldwide. Metric sockets and screws are primarily measured in millimeters.

You can use the chart below to convert an SAE size to metric. You can also do the conversion by hand in a few easy steps as follows:

Step One: Convert the Inch Fraction to an Inch Decimal

The first step is to convert the inch fraction to a decimal. You can do this by treating the fraction as a division problem and solving it.

For instance: 1/4″ = 1 ÷ 4 = 0.25″

Step Two: Convert the Inch Decimal to Millimeters

The next step is to multiply the inch decimal by 25.4 to convert it to millimeters. This is the key step for converting SAE to metric.

0.25″ × 25.4 = 6.35 mm

SAE to Metric Conversion Chart

The chart below shows SAE measurements (in fractions) and the equivalent metric and inch decimal measurements for common socket, wrench, and screw sizes.

SAE to metric conversion chart showing equivalent standard and metric measurements

Standard (SAE)	Metric (mm)	Inches (decimal)
1/32″	0.7938 mm	0.0313″
1 mm	0.0394″
1/16″	1.5875 mm	0.0625″
5/64″	1.98438 mm	0.0781″
2 mm	0.0787″
3/32″	2.3813 mm	0.0938″
7/64″	2.7781 mm	0.1094″
3 mm	0.1181″
1/8″	3.175 mm	0.125″
5/32″	3.9688 mm	0.156″
4 mm	0.157″
4.5 mm	0.177″
3/16″	4.7625 mm	0.188″
5 mm	0.197″
5.5 mm	0.216″
7/32″	5.5563 mm	0.219″
6 mm	0.236″
1/4″	6.35 mm	0.25″
6.5 mm	0.256″
7 mm	0.276″
9/32″	7.1438 mm	0.281″
5/16″	7.9375 mm	0.313″
8 mm	0.315″
11/32″	8.7313 mm	0.344″
9 mm	0.354″
3/8″	9.525 mm	0.375″
10 mm	0.394″
13/32″	10.3188 mm	0.406″
11 mm	0.433″
7/16″	11.1125 mm	0.438″
15/32″	11.9063 mm	0.469″
12 mm	0.472″
1/2″	12.7 mm	0.5″
13 mm	0.512″
17/32″	13.4938 mm	0.531″
14 mm	0.551″
9/16″	14.2875 mm	0.563″
15 mm	0.591″
19/32″	15.0813 mm	0.594″
5/8″	15.875 mm	0.625″
16 mm	0.63″
21/32″	16.6688 mm	0.656″
17 mm	0.669″
11/16″	17.4625 mm	0.688″
18 mm	0.709″
23/32″	18.2563 mm	0.719″
19 mm	0.748″
3/4″	19.05 mm	0.75″
25/32″	19.8438 mm	0.781″
20 mm	0.787″
13/16″	20.6375 mm	0.813″
21 mm	0.827″
27/32″	21.4313 mm	0.844″
22 mm	0.866″
7/8″	22.225 mm	0.875″
23 mm	0.906″
29/32″	23.0188 mm	0.906″
15/16″	23.8125 mm	0.938″
24 mm	0.945″
1″	25.4 mm	1″

More Standard to Metric Conversions

You can use our inches to mm conversion calculator to convert SAE measurements to metric. You can also convert these common sizes by using the links below:

• 17/32 to mm
• 9/16 to mm
• 19/32 to mm
• 5/8 to mm