Writing Style – Metric or Imperial

When should I use metric as opposed to imperial measurements?

Although the Canadian style is to use metric for most measurements, there are a few exceptions, such as personal weights and heights, two-by-fours, quarter-inch screws, some sports, etc.


A three-kilogram packet costs $4.

She is 5 feet 8 inches tall. (Always use numbers rather than words for dimensions, sizes and temperature readings.)

Normally, when you are using measurements, spell out terms such as foot, hundredweight, kilogram, and metre.

Some common terms — mm, m.p.h., c.c., km/h — may be used when mentioning them a second time. The only exception is C (for Celsius), which can be used on first reference.


The temperature was 40 C.

Use this style for imperial abbreviations, both singular and plural:

In .   ft.     yd.    mi.    oz.    lb.


Her golf drives are normally 250 yd. long.

There are no abbreviations in metric, only symbols. Therefore, use this style for metric measurements, both singular and plural:

mm    cm      m       l      kg      km

Notice: There are no periods in these symbols – only for the end of a sentence.??The boardroom is 6 m x 10 m. (Technical usage)

The boardroom is 6 x 10 m. (General usage)