6 Countries That Still Use Imperial Units (And Why)

Only 3 countries have never officially adopted the metric system, but several more still use imperial units in daily life despite going metric on paper. Here’s the real picture.

1. United States

The US legalized metric use back in 1866 and is a founding signatory of the 1875 Treaty of the Metre, but never mandated full conversion. Today it runs a genuine mixed system: seconds and liters (wine, spirits) are metric, while gasoline (gallons), height (feet/inches), and weight (pounds) remain stubbornly imperial.

2. Liberia

Founded by former US slaves in 1822, Liberia retained US customary units as part of its American heritage. Metric is the official system on paper, but enforcement is weak, and legal documents still commonly use pounds, feet, and gallons.

3. Myanmar

Myanmar’s military government banned metric adoption between 1962 and 2011 to preserve traditional units. Traditional Burmese units (like the “pya,” roughly 1.3 kg, used for rice) and miles-based road signs remain common, though modernization efforts have picked up since the 2011 democratic transition.

4. United Kingdom

The UK is officially metric and converted most of government, industry, and science decades ago, but imperial units remain legally mandated for specific things: road signs (miles), draft beer and cider (pints), and returnable milk containers (pints) are all required by law to stay imperial.

5. Canada

Canada is officially metric, but imperial units persist informally, especially in cooking (cups, tablespoons) and everyday references to a person’s height and weight, much like the US.

6. India, Australia, and South Africa

All three are fully metric nations, but as former British territories, imperial holdovers still surface casually, particularly for height, weight, and some cooking measurements, a cultural residue of Britain’s own imperial history.

Why the imperial system hangs on

• Cost of conversion: replacing road signs, packaging, and infrastructure at national scale is expensive and disruptive.
• Industry standardization: aviation, shipping, and some manufacturing sectors built decades of imperial-based standards that are costly to replace.
• Public familiarity: surveys consistently show strong public resistance to switching, even among people who understand the metric system.

Whichever system you’re converting between, our unit conversion calculator handles length, weight, temperature, and volume instantly, and see our list of real disasters caused by unit conversion mistakes for why getting this right matters.