The foot is defined as 12 inches, each inch is 25.4 millimeters. A meter is defined as "the length of the path travelled by light in vacuum during a time interval of 1/299792458 of a second." So the foot is defined in terms of exact rational seconds.
NIST offers calibration and measurement services for length.
http://nist.gov/calibrations/dimensional_links.cfm "Traceability to NIST" http://nist.gov/traceability/index.cfm is a big deal to people who care about calibration in the US. NIST and other national calibration labs circulate "transfer standards" amongst each other in order to ensure international agreement.
Comments
The foot is defined as 12 inches, each inch is 25.4 millimeters. A meter is defined as "the length of the path travelled by light in vacuum during a time interval of 1/299792458 of a second." So the foot is defined in terms of exact rational seconds.
NIST offers calibration and measurement services for length. http://nist.gov/calibrations/dimensional_links.cfm "Traceability to NIST" http://nist.gov/traceability/index.cfm is a big deal to people who care about calibration in the US. NIST and other national calibration labs circulate "transfer standards" amongst each other in order to ensure international agreement.
each inch is 25.4 millimeters.
Huh, I missed that development. https://en.wikipedia.org/wiki/Inch#Modern_standardisation
Just to be sure, I'll keep a few aristocrats' appendages in my toolbox, for reference should a real foot needed...