Achtelzoll

Achtelzoll is an obsolete unit of length that was used in German-speaking regions. It denotes one eighth of a Zoll, the traditional inch, so eight Achtelzoll make up one Zoll. Because the Zoll varied regionally and over time, the exact length of an Achtelzoll differed by locale and historical period.

In the metric era, it is often approximated by converting to millimeters: with a Zoll of about 2.54 centimeters, one Achtelzoll would be roughly 3.2 millimeters, but actual values could vary with local standards.

Achtelzoll appeared in crafts such as carpentry, cabinetry, metalworking, and textile patterning, as well as in early drawings and instrument scales. It was primarily used in practical measurement contexts and in trade documentation rather than as a formal, standardized unit.

With standardization efforts and the adoption of the metric system in German-speaking territories during the 19th and early 20th centuries, the Achtelzoll fell out of use and is now encountered mainly in historical texts, antique furniture descriptions, or studies of old measurement practices.

Etymology: the name derives from achtel- “eighth” and Zoll “inch.” See also related units such as Zoll, Linien, and Leinenmaß for broader context of historical German measurement systems.