Why does the metric system use prefixes

A prefix represents a factor by which the base unit must be multiplied. Metric prefixes are listed below The prefixes most-commonly used in chemistry are listed in red : Prefix Symbol Decimal Value Power of Ten Exa- E 1,,,,,, 10 18 Peta- P 1,,,,, 10 15 Tera- T 1,,,, 10 12 Giga- G 1,,, 10 9 Mega- M 1,, 10 6 Kilo- k 1, 10 3 Hecto- h 10 2 Deka- da 10 10 1 no prefix 1 10 0 Deci- d 0.

Scaling the unit up or down when reporting measurements is good practice because: It can be used to keep the numeric value of measurements to reasonably-sized numbers, say between values of 0. It can be used to remove ambiguous place-holding zeroes in measurments, so that the number of significant figures are properly represented. The prefixes instantly convey how many decimal place moves are required of the numeric value.

Likewise, they can mean a fraction of a unit rather than a multiple. So a millimetre is one thousandth of a metre. Put another way, there are one thousand millimetres in a metre. These prefixes can be applied to any fundamental metric unit like the metre for distance, the gram for mass or weight, the watt for power, and so on. Traditional measurement units that were used before the metric system had their own distinct names like stone, pound and ounce for weight or yard, foot and inch for distance.

Some people criticise the metric system because of the long multisyllable names it gives rise to as a result of the prefixes. The table below includes the most commonly encountered prefixes based on multiples or subdivisions of Skip to content Explanation of prefixes A metric prefix is a convenient way of expressing mulitiples and subdivisions larger and smaller of any defined unit.

These include:. Now that we know the units, let's look at how they can be augmented with prefixes to make them even more usable! These are what we'll consider the standard six prefixes taught in most High School science courses. However, as you'll soon see, when learning about electronics and computer science, the range of prefixes well exceeds the standard six. While these prefixes cover a rang of 10 -3 to 10 3 , many electronic values can have a much larger range.

These above prefixes dramatically help describe quanities of units in large amounts. Instead of saying 3,,, Hertz, you can say 3. This allows us to describe incredibly large numbers of units succinctly. There are also prefixes for helping communicate tiny numbers as well. Now, instead one trillionth of a second, it can be referred to as a picosecond. This allows you to distinguish between the two when they use the same letter.

As an example, one mW milliwatt does not equal one MW megawatt. As you'll see in the Bits and Bytes section , there is also some confusion with k and K when dealing with the binary base 2 prefixes. The beautiful thing about these metric prefixes is that, once you get the hang of conversion between a few of them, translating that ability to all the other prefixes is easy. As a first simple example, lets translate 1 Ampere A into smaller values. A milliampere is 1 thousandth of the unit Ampere hence 1 Ampere is equal to milliamperes.

Going further, 1 milliampere is equivalent to microamperes and so on. Going in the opposite direction, 1 Ampere is. Now that's a lot of current! As you may have noticed, switching between prefixes is the same as moving the decimal point over by 3 places. This is also the same as multiplying or dividing by When you're going up to a larger prefix, from Kilo to Mega for example, the decimal place is moved three places to the left.

Mega is the prefix right above Kilo so regardless of whether we are talking about Watts, Amperes, Farads, or whatever unit, the movement of the decimal place by three positions to the left still works when moving up a prefix.

When moving down a prefix, let's say from nano- to pico-, the decimal place is moved three places to the right. Here's a short list so you can see the pattern:. See the trend? Each prefix is a thousand times larger than the previous. While a little overwhelming at first, translation from one prefix to another eventually becomes second nature. Working with bits and bytes can cause a bit confusion pun intended. Since computers work with base 2 numbers instead of base 10, it is often unclear which number base one is referring to when using the metric prefixes.

For example, 1 Kilobyte is often used to mean bytes base 10 , or it can be used to represent bytes base 2 , resulting in misunderstandings. To eliminate these mix-ups, the International Electrotechnial Commision came up with some new prefixes for the base 2 bits and bytes. These are referred to as binary prefixes. Unfortunately, this system is not widely used in practice, so anytime you hear a number of bytes or bits, you have to wonder if they are talking about them in base 2 or base Hard drive companies and others typically sell products in base 10 as it makes it sound larger.