This expression means a rough estimation, guide or approach, often based on experience and not on science or exact measurement. The origin of the saying is unknown. It is likely that the phrase refers to one of the numerous ways that thumbs have been used to estimate things - judging the alignment or distance of an object when precise accuracy is not needed. The phrase has been in circulation since the 1600s. The first reference in print is from 1692.

Übersetzung:

Faustregel

Gegenteil(e)

The opposite of "rule of thumb" is "accurate measurement".

Synonym(e):

You could also say: a method that comes from practise, without any formal basis.