How to convert nut dimensions

Updated February 21, 2017

Nuts that are used to secure bolts come in two distinct measurements: metric (millimetres) and imperial measure (Inches). The size of the nut is determined by the diameter of the hole. You can easily convert the dimensions of a nut from metric to inches or from inches to metric. This allows you to substitute a metric nut for an English nut when a replacement nut is needed for a project.

Measure the diameter of a nut with the ruler. Make a note of the measurement, such as 3/8 of an inch.

Divide 3 by 8 for a result of 0.375. Multiply 0.375 by 25.4 (the number of millimetres in an inch) for a result of 9.525.

Round 9.5525 up to the next whole number which is 10 millimetres (mm). This is the size of a 3/8-inch nut when it its dimension is converted to metric.

Measure the diameter of a nut with the metric ruler. Make a note of the measurement, such as 7mm.

Multiply 7mm by 25.4 for a result of 0.275. Write 0.27 as a fraction. This will look like 27/100.

Reduce the number 27 to 25 which will divide into 100. Divide 25 by itself for a result of 1. Divide 100 by 25 for a result of 4. The resulting nut size is 1/4 of an inch.

Things You'll Need

  • Metric ruler
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About the Author

Cameron Easey has over 15 years customer service experience, with eight of those years in the insurance industry. He has earned various designations from organizations like the Insurance Institute of America and LOMA. Easey earned his Bachelor of Arts degree in political science and history from Western Michigan University.