When to switch Metric Terms

[RMDavis]

Hi All -

Kinda of an odd question, but...  When does one switch from using mm to cm or m?  Is there a specific length suggested for when to swap to the next larger unit of measurement? 

Asking as I have to occasional tech document to write.

TIA

Ross

 

[Stephen B]

Do not swap when measuring, stick to mms. Building plans are mainly in mms to avoid confusion; eg, the cabinet in 70mm high, the wall is 5000mm long.

However when purchasing timber, it can be referred as in mms or metres - 5.4 metres or 5400mm. However it is more common for the price tag to read 5.4metres.

CentreMetres are seldom used, other than as a reference on a ruler for counting multiples of 10 or 100mms.

 

[Wuffles]

I try not to confuse things and stick to mm. However, when you get into metre territory then talking in the tens of thousands goes out of the window. Don't forget you don't lose any accuracy as you're dealing in decimal and can add a decimal point to get to the nitty gritty.

What he said.

 

[keithu]

In technical writing with SI units it's the convention to use only prefixes that represent powers of 1000. That's giga-, mega-, kilo-, milli-, micro-, nano- etc.  So cm don't get a look in.

 

[RMDavis]

In technical writing with SI units it's the convention to use only prefixes that represent powers of 1000. That's giga-, mega-, kilo-, milli-, micro-, nano- etc.  So cm don't get a look in.

And convention was the word escaping me as I wrote the question.  Most appreciated!

 

[Kev]

mm all the way [wink]