Reading a Metric Micrometer

An outside micrometer.

Metric micrometers are similar to standard micrometers. There are markings on the sleeve and the thimble. Notice the sleeve of a metric micrometer has markings on the top and the bottom. There is a handle lock and a ratcheting end to ensure that the same pressure applies to all readings.

Metric micrometer.

Whole number increments are on one side of the sleeve, and half-millimeter increments are on the other. Depending on the manufacturer, these .50-millimeter or half-millimeter increments may be on the top or the bottom. The micrometer in the illustration has them on the bottom. The thimble of the micrometer has increments of .01 millimeters. Note that 50 divisions of .01mm are notched on the thimble of a metric micrometer.


The micrometer on the top is set to 6.50 mm. There are six whole millimeters on the top and half a millimeter on the bottom. The thimble is at 0. The three added together equal 6.50 mm. It is important to remember that increments are marked on both sides of the sleeve. A complete turn of the thimble will result in .50 mm or half of a millimeter.

The micrometer on the bottom is 6.55mm. First, add the whole number, which is 6 millimeters. Then, add the .50 millimeter on the other side of the sleeve. Finally, add the five .05 millimeters on the thimble, totaling 6.55.