The age-old conundrum, why do we need two systems of measurements? Get comfy readers, this blog post will take a while to get through. As you might be aware, there are two major systems for measuring distances and weight around the world, the Imperial System of Measurement and the Metric System of Measurement (SI). Most countries use the Metric System, which uses the measuring units such as meters and grams. We add prefixes like kilo, milli and centi to count orders of magnitude. However in the United States, people still use the older Imperial system. Readings are measured in feet, inches and pounds. Over the years, manufacturers have awoken to the acute problem of converting between these two units of measurement and have now begun to add conversion tables to toolsets. Tape measures for instance have been carrying measurements in both inches and centimetres for the longest time. Still, for larger units like kilometres and miles, conversions can be hectic.

The Imperial System (also called The British Imperial) because it came from the British Empire (surprise, surprise!) which ruled over many continents between the 16th and the 19th century. Despite gaining independence from Britain, the government of United States of America decided to stick with imperial units. Here are a few handy conversions to keep in mind when working with metric or imperial units:

– 1 mile equals 1.6 kilometres.
– 1 inch is about 25 millimetres or 2.54 centimetres
– A 3-foot measurement is almost exactly 1 meter
– 1 Kilogram is just over 2 pounds
– 1 pound is about 454 grams
– For British visitors, 100 pounds = 7.14 stone

What is the Foot?
We are not talking about limbs here, obviously! The foot is a unit of length in the imperial system of measurement. It is defined by international agreement as equivalent to 0.3048 meters exactly. The foot, which is the plural form of feet, comprises of twelve inches and 3 feet compose 1 yard.

Over history, the “foot” has been a part of many local systems of units. These systems include the Greek, Roman, Chinese, French, and English measurement systems. For years, it varied in measured length from country to country, from city to city, and sometimes even from trade to trade.

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USA is the only industrialized nation in the modern world which utilizes the international foot over the meter in its commercial, engineering, and standards activities. This makes it difficult for first time travellers as they have to deal with conversion tables. has you covered though! We have conversion tables in all our calculators. Moreover, you might not need them anyway as you can enter values in both SI and metric units and get results in any desired unit at the click of a button. Check out our Square Footage Calculator and Square Inches Calculator

What is the Metre?
The origin story of the metre goes back to the 18th century. Yes, this is interesting. At that time, it was proving tough for scientists and researchers to reach a consensus on which of the two competing approaches to its definition should be adopted. Some suggested defining the metre as the length of a pendulum having a half-period of one second; others insisted that defining the meter as one ten-millionth of the length of the earth’s meridian along a quadrant (one fourth the circumference of the earth). Both those definitions are complicated if you ask us!

According to research data present online, in 1791, soon after the French Revolution, the French Academy of Sciences chose the meridian definition over the pendulum definition because the force of gravity varies slightly over the surface of the earth, affecting the period of the pendulum. This length became the standard. Research states that, “In 1927, the meter was more precisely defined as the distance, at 0°, between the axes of the two central lines marked on the bar of platinum-iridium kept at the BIPM, and declared Prototype of the meter by the 1st CGPM, this bar being subject to standard atmospheric pressure and supported on two cylinders of at least one centimetre diameter, symmetrically placed in the same horizontal plane at a distance of 571 mm from each other.”

The 17th General Conference on Weights and Measures (1983) passed a resolution which clarified the definition of the metre further, “…thus fixing the length of the metre in terms of the second and the speed of light: The metre is the length of the path travelled by light in vacuum during a time interval of 1/299792458 of a second.”

Interesting fact
There are numerous ‘metric’ countries which are similar to the USA, in that that they, at least in practice, use a combination of metric and traditional measurements. The unusual thing about USA is that they are one of the few countries that is not officially metric under law! However, under the Omnibus Trade and Competitiveness act of 1988, the U.S. has declared metric to be “the preferred system for US trade and commerce”. This makes it easier for manufacturers and users importing and exports tools and instruments across US borders to gain a larger market for their goods and services.

So use metres or use feet, just make sure you measure correctly and enter the right values in our area calculators. This way you will get accurate results every time regardless of the system you use.

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