its actually spelled,
metres

1:10 can mean
1mm = 10 mm
1 cm = 10 cm
etc...

In order to convert with a fraction, you need to convert the imperial scale to a ratio. for example 1/8" scale is 1:96. 1/4" scale is 1:48, 1/2" = 1:24. Metric scales work this way.

1:100 is close to 1:96, 1:50 is close to 1:48, etc. 1:10 is close to 1:12, etc.

I sort of recall that to get a scale of 1:150 metric, you had to set your scale to 0.262 something something something...

I don't recall the rest, but that should get you in the ballpark... or maybe it's just me that is out of the ballpark. :)

dolemite is correct.
by 1/xp i assume you are talking about autocad. i don't know any european firms that use that program. minicad, archicad, vectorworks were mainstream...

and it is metre in GB and FR, but not in germany, NL, austria or switzerland. i believe all those are meter, if my memory serves me correct.

we draw everthing in millimeters here in the UK, always have.

maybe not before decimilisation in the mid 70's

I use this abacus.

1:10.000 __ 10m = 1 mm
1:5.000 __ 10m = 2 mm
1:2.000 __ 10m = 5 mm
1:1.000 __ 1m = 1 mm
1:500 __ 1m = 2 mm
1:200 __ 1m = 5 mm
1:100 __ 1m = 1 cm
1:50 __ 1m = 2 cm, 10 cm = 2 mm
1:20 __ 1m = 5 cm, 10 cm = 5 mm
1:10 __ 1m = 10 cm, 1 cm = 1 mm
1:5 __ 1m = 20 cm, 1 cm = 2 mm
1:2 __ 1m = 50 cm; 1 cm = 5 mm

dolemite:

it's the opposite of what u said, because the scale 1/x means that the measures u draw on the paper are less than the real measures.
the scale x/1, istead, means that u are actually magnifying the object, so the measures on the paper must be higher tha the real measures.

Aw, c'mon and explain it in a clear way:

deci = tenth (0.1)
centi = hundredth (0.01)
milli = thousandth (0.001)
micro = tenthousandth (0.0001)
etc.

which means that

ten decimeters = 10 x 0.1m = one meter
a hundred centimeters = 100 x 0.01m = one meter
a thousand millimeters = 1000 x 0.001m = one meter

Scale 1:N means that 1 length unit in the drawing corresponds to N units in real life (world space?).

So, one millimeter in the drawing means N millimeters.
Two millimeters in the drawing means two times N millimeters.
One inch in the drawing is one times N inches.
Five feet in the drawing is five times N feet.

Therefore scale 1:1000 means that one centimeter (one hundredth of a meter, i.e. 0.01m) in the drawing corresponds to 0.01m x 1000 = 10 meters. Similarly, a distance of five meters is drawn as 5m / 1000 = 0.005m = 5 millimeters.

If you use metric mode in AutoCAD you can just set the viewport scale directly to "1:N", there's no need to write 0.262..... if you draw something in scale 1:150. (0.262 is 1/150 by the way) Usually such scales are not used anyway, most common are the ones mentioned by matteo.

the most common scales in architecture are:

1/1 - the constructed building
1/5 - component detail
1/10 - large detail
1/20 - standard detail
1/50 - detail sections / elevations / plans
1/100 or 1/200 - general plans elevations in context
1/500 - block plan
1/1250 - Ordinace Survey maps (OS)

what is slightly anoying is that OS and many engineers measure everything in metres so you have to scale by 1000 to get it all to scale the same.

Patrick - we will allow 5mm tollerance if they are a bit slack