Imperial Fasteners vs. Metric FastenersPhoto by Mika Baumeister

Originally Posted On: Imperial Fasteners vs. Metric Fasteners (


Do you know what the differences between American Standard (imperial) fasteners and metric fasteners are? If you’re choosing fasteners for a particular application, it will be important to know these differences.

Sometimes, the choice between using imperial fasteners or metric fasteners are just a matter of preference. Other times, it may depend on the market you’re selling your end product to – if your target market is using metric fasteners regularly, it would be wise to stick with metric fasteners. This is why some manufacturers who are based in the United States where imperial fasteners are standard, but sell more volume in Europe where metric fasteners are standard, choose to use metric fasteners in their products.

If you need to use a wide variety of sizes within a relatively small range for your application, then metric fasteners may be a better choice, since they scale in size more easily than standard fasteners. Also easier is the process of subdividing units of measurement in the metric system.

We created a chart to help you sort through the differences in materials, mechanical properties, markings, thread sizes, tensile strengths and more.

If you still have questions about the differences between metric and imperial fasteners not addressed in this chart, just contact us, we’ll be happy to help.