How large is a micrometer (µm)?

A micrometer (µm) corresponds to one thousandth of a millimeter (1µm = 0.001 mm).
For illustration: a human hair is approx. 60 µm thick. In this post, we have shown further size comparisons.
Our measuring microscopes measure with accuracies in the range of 1–2 µm. Gauge blocks can have accuracies of approx. 0.1 µm.