Metric Basics


The metric system was first devised in the late 1700s as a means of standardising and simplifying the many weights and measures that existed at that time. Not only did similar sounding measures differ from country to country, but regional or even town-to-town differences were commonplace.

The metric system was rapidly adopted in European countries during the 19th century and has spread to most of the world since. The development of the metric system also became an international effort with significant proposals from British scientists in the 1860s.

The Base Units

  • Unit of mass: kilogram
  • Unit of length: metre
  • Unit of time: second
  • Unit of electric current: ampere
  • Unit of thermodynamic temperature: kelvin
  • Unit of amount of substance: mole
  • Unit of luminous intensity: candela

Some of these units might not be familiar to most people, but derived units from those are, such as degrees Celsius derived from kelvins for temperature, electrical power measured in watts derived from amperes, and volume is just length cubed. Time in seconds is universal and everyone should know that there are 60 seconds in 1 minute, and 60 minutes in 1 hour. Some of the derived units use hours, such as velocity (speed) in kilometres per hour. Note also that the term mass is used instead of weight, as weight is not a constant and can vary, and mass is what kilograms actually measure. Weight is a force, which is measured in newtons.

Please look at the pages on this website to explain further the main units and how to use them. Click on your choice here, or view the other links on the site in the menu at the top/bottom of the pages:


Once you know the basic and derived units and their relationships with each other, it is easy to work with them on a daily basis. Once you are familiar with them, it will be much easier to think metric — it’s not rocket science, you do not need a degree to understand the system nor for using it every day, just to know how each unit is used and to think of things that relate to the different metric measurements. It is by far the easiest measurement system devised by mankind to date, and takes very little time to learn.

“…no nation which has adopted the Metric system has failed to derive the greatest benefit from such adoption, or, after adoption has shown any desire to abandon it.”
Report from the Select Committee on Weights and Measures (1862).


The metre is the standard of length, which is divided into 100 centimetres, also into 1000 millimetres. 1000 metres is the same as 1 kilometre. And we can also see that 10 millimetres is the same as 1 centimetre. These distances can all be abbreviated to 1 or 2 letters for ease of use, especially… Continue reading Length


Want to know how fast something is? How quickly it moves and how long it will take to get somewhere? If you know the speed then you can. In metric, speed is usually measured in kilometres per hour. The kilometre is a unit of length. Another unit of length, the metre, can be also be… Continue reading Speed


Area is the measure of how much space something takes up on the ground, floor, wall or other flat surface. Note that by flat we do not mean totally flat, as a ball has a surface area too, just that we mean flat as in not measuring the thickness as well, as that is covered… Continue reading Area


Metric Weight / Mass Most people are familiar with the word “weight”, some may also know the term “mass”. For most things in everyday usage, they mean pretty much the same. You might come across the term “mass” in reference to body mass or your BMI (body mass index). It is just a case of… Continue reading Mass


What is volume? It is a word that can have several meanings, such as a number in a series of books; but in terms of measurement we are looking at how much space an object or liquid occupies. For example, if I have an empty bottle and want to fill it up, how much liquid… Continue reading Volume


Temperature is measuring how hot or cold something is, such as the outside air temperature, your body temperature, temperature of water for cooking, boiling, washing, etc. So, is it cold or hot when the temperature forecast says it will be 5 degrees or it will be 30 degrees? What temperature does water freeze at? Or boil at?… Continue reading Temperature