How long has the metric system been legal in the United States?

BungeeAZ

The metric system has been taught in the schools since the 70's, but it is still not the "legal" system in the US as we still measure gas and milk by the gallon, not by the liter, land is in acres, not by the hectaire. Scientists use the metric system so that results are compatible with results from Europe. May 31 07, 3:19 PM

Baloo55th

I'll refer you back to the question. How long has the metric system been legal in the USA? May 31 07, 3:51 PM

star_gazer

Metrication in the United States has been unsteady. In some fields, the metric system has been used in the United States since the early 1800s. The use of metric units has been gradually increasing for many years, but much of the public momentum has been lost since the 1980s, except in schools, science, and manufacturing. http://en.wikipedia.org/wiki/Metrication_in_the_United_States May 31 07, 3:58 PM

Baloo55th

True, but still not answering the question. There IS an answer..... May 31 07, 4:02 PM

BADMAN420

1866: The use of the metric system made legal (but not mandatory) in the United States May 31 07, 5:55 PM

MonkeyOnALeash

Avoirdupois, Kelvin, "SI", Apothecaries and Imperial (Brirish) are used in America. I do not think that any system is legal or illegal. So long as the scales are true, the consumer is consulted and informed concerning the units of measure and an agreement is made between the parties concerned, any recognized system is "legal". http://ts.nist.gov/WeightsAndMeasures/Publications/upload/h4402_appenc.pdf May 31 07, 7:20 PM

Baloo55th

And a Yay! for Badman. The metric system was made legal in the USA in 1866 (as it says further down the page in star_gazer's site!) and standard measures were sent to all the states. However, people get confused between legal and compulsory. Something may be legal but you don't have to do it. Like drinking in a bar. It's legal for over 18s in the UK, but they don't HAVE to do it. A shop in the USA can sell dried peas by the kilo but not by the mahnd, for example. Jun 01 07, 3:42 AM