Editing Micrometer (device) (section)

===Vernier micrometers===
[[File:5783metric-micrometer.jpg|thumb|Vernier micrometer reading 5.783&nbsp;±&nbsp;0.001&nbsp;mm, comprising 5.5&nbsp;mm on main screw lead scale, 0.28&nbsp;mm on screw rotation scale, and 0.003&nbsp;mm added from vernier]]
Some micrometers are provided with a [[vernier scale]] on the sleeve in addition to the regular graduations. These permit measurements within 0.001&nbsp;millimetre to be made on metric micrometers, or 0.0001&nbsp;inches on inch-system micrometers.

The additional digit of these micrometers is obtained by finding the line on the sleeve vernier scale which exactly coincides with one on the thimble. The number of this coinciding vernier line represents the additional digit.

Thus, the reading for metric micrometers of this type is the number of whole millimeters (if any)  and the number of hundredths of a millimeter, as with an ordinary micrometer, and the number of thousandths of a millimeter given by the coinciding vernier line on the sleeve vernier scale.

For example, a measurement of 5.783&nbsp;millimetres would be obtained by reading 5.5&nbsp;millimetres on the sleeve, and then adding 0.28&nbsp;millimetre as determined by the thimble. The vernier would then be used to read the 0.003 (as shown in the image).

Inch micrometers are read in a similar fashion.

Note: 0.01 millimeter = 0.000393&nbsp;inch, and 0.002&nbsp;millimeter = 0.000078&nbsp;inch (78 millionths) or alternatively, 0.0001&nbsp;inch = 0.00254&nbsp;millimeters. Therefore, metric micrometers provide smaller measuring increments than comparable inch unit micrometers—the smallest graduation of an ordinary inch reading micrometer is 0.001&nbsp;inch; the vernier type has graduations down to 0.0001&nbsp;inch (0.00254&nbsp;mm). When using either a metric or inch micrometer, without a vernier, smaller readings than those graduated may of course be obtained by visual interpolation between graduations.