An anti-metric system poster from 1917 United States of America.

If you live in the U.S., you probably drive 8 miles to work, use 11 gallons of gas, weigh 150 pounds, and fix your fence with a 1/2″ screw. On the European continent, you’ll use 43 litres of gas, go 12 kilometres, weigh 68 kilograms, and put a 12.5 mm screw in your fence.

In the UK, you would put 43 litres of gas in your car, drive 8 miles to work, weigh 10 stone and 7 pounds, and fix your fence with a 12.5 mm screw. Most of the time, this just causes confusion, but sometimes the results are much worse. In a well-known case of confusion between imperial and metric units, NASA lost the Mars Climate Orbiter. If you’re using BricsCAD, follow our detailed instructions on how to change the drawing units.

What is going on, and why is everyone so confused about it?

Measuring things can be different depending on where you are. Since the beginning of trade, people have used measurements. Weights and measures were first used in the 3rd and 4th millennia BC, and, as you might expect, they were different in each region.

Arms, grains, and steps

At first, seeds and grains were used to measure weight and volume because they were pretty stable. The carob seed is the source of the carat, which is still used to measure precious stones. The problem was that it could take a long time to count all of the seeds that were needed to fill a jar. Body parts were often used as units for measuring. The cubit was used by the Egyptians, the ancient Indians, and the Mesopotamians. It was the distance between the elbow and the tip of the middle finger. But using this as a standard is a terrible idea. Instead of going shopping yourself, ask your friend with the longest arms to do it for you. As a solution, the Egyptians came up with a standard rod that had clear measurements written on it.

The same thing would happen in a yard. Before, this was how long a man’s belt was. At last, a reason to go too far! The Romans came up with the mille passus unit of measure, which is equal to 1000 double steps. The modern mile is about 280 feet longer than this (85 metres). If you’ve ever seen a short person and a tall person walk side by side, you’ll know how much this measurement is off.

Wide-ranging Network

In the 10th century, Edgar the Peaceable, a Saxon king, set up the British imperial system, which became known as the “Winchester” system. He used a regular bushel ( 35.2 l or 9.3 US gal). Before, traditional terms like “foot” and “gallon” were used, but they were used in a very casual way. The real values of these metrics varied a lot depending on where they were used, when they were used, and even what was being traded. In the 1400s, the first yard was officially measured at 3 feet. This replaced the old unit of measurement, which was a man’s thumb width, which was 12 inches. King Henry VII made changes to the Winchester standards in the 1500s.