Countries using the metric, US customary and imperial systems of units as of 2019. Only the USA uses the US customary system; Liberia, Samoa, Palau, Micronesia, and Marshall Islands use unknown (i.e. it is unclear which system they use) non-metric systems; it is impossible to clearly determine which system Burma uses; the UK and Canada use a mixture of imperial and metric systems.
<a href="//commons.wikimedia.org/wiki/User:Goran_tek-en" title="User:Goran tek-en">Goran tek-en</a>, following request by and knowledge from <a href="//commons.wikimedia.org/wiki/User:Veverve" title="User:Veverve">Veverve</a>
CC BY-SA 4.0
<p><span class="int-own-work" lang="en">Own work</span><br>
This file was derived from: <a href="//commons.wikimedia.org/wiki/File:BlankMap-World.svg" title="File:BlankMap-World.svg">BlankMap-World.svg</a><br>
Information from:
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<ul><li><a rel="nofollow" class="external text" href="https://www.statista.com/chart/18300/countries-using-the-metric-or-the-imperial-system/">StatistaCharts</a> (very faulty, see talk page)</li>
<li>Vera, Hector (September 2011), <i><a rel="nofollow" class="external text" href="https://pqdtopen.proquest.com/doc/924487292.html?FMT=AI">The Social Life of Measures: Metrication in the United States and Mexico, 1789–2004</a></i> (PhD) (in English), The New School for Social Research of The New School</li>
<li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20210101232130/https://www.cia.gov/library/publications/the-world-factbook/appendix/appendix-g.html">CIA World Factbook - appendix G</a></li>
<li><a rel="nofollow" class="external text" href="https://blog.ansi.org/2018/06/us-customary-system-history-units/">American National Standards Institute</a>, <a href="https://en.wikipedia.org/wiki/Metric_Conversion_Act" class="extiw" title="w:Metric Conversion Act">w:Metric Conversion Act</a>, <a href="https://en.wikipedia.org/wiki/Metrication_in_the_United_States" class="extiw" title="w:Metrication in the United States">w:Metrication in the United States</a></li>
<li><a href="https://en.wikipedia.org/wiki/Metrication_in_Canada" class="extiw" title="w:Metrication in Canada">w:Metrication in Canada</a>, <a rel="nofollow" class="external text" href="http://angusreid.org/metric/">Angus Reed Institute</a>, <a rel="nofollow" class="external text" href="https://www.rcinet.ca/en/2017/03/02/canada-still-confused-about-measuring-since-1975/">Radio-Canada International</a>, <a rel="nofollow" class="external text" href="https://wernerantweiler.ca/blog.php?item=2015-01-01">Prof. Werner Antweiler, Ph.D.</a></li>
<li><a href="//commons.wikimedia.org/wiki/User:Veverve" title="User:Veverve">Veverve</a> (this doesn't mean much in terms of authority, unless this particular user's sources are revealed)</li></ul>