# What are the units for tenths-of-a-millimeter?

I'm seeing all kinds of mixed representations for what is a SI unit that doesn't seem to be easily representable with the Latin prefixes. Generally I stick one of the nominal ones and scale my plots accordingly but this situation requires a particular scale/resolution of tenths of a millimeter:

dmm = deci-milli-meter

tmm = tenths-of-a-milli-meter

https://en.wikipedia.org/wiki/Metric_prefix

• You could label your scale as "mm/10" or "0.1 mm" Commented Apr 2, 2016 at 18:36
• Something like "axis label ($\times 10^{-4}$ m)" would be most common in a research paper... Commented Apr 2, 2016 at 18:46

## 3 Answers

I have never seen anything like tmm or dmm... If it exists at all, it is highly non-standard. As others have mentioned in the comments, go with 0.1 mm or 100$\mu$m. I think that the conventional way of writing is $10^{-1}mm$.

• FYI, 10th of millimeters is the unit used for Li-Ion battery lengths. ala a "18650 cell", where 650 is 650 tenth of millimeters = 65mm length. The first two digits is the diameter in mm. Also to super nitpick "non-standard", this is supposedly standardized in "IEC standard 60086-1" according to Wikipedia (though I couldn't find a free pdf source to verify it). Commented Jun 27, 2021 at 9:45

You can also use micrometer, and write $100\mu m$.

If you want to use SI nomenclature, that the following is acceptable: $0.1 mm = 0.1 mm (!), 100 \mu m = 100 000 nm ...$. How you wish to record it is up to you, though problem dependent. For example, you could record a $9 V$ battery as $9 000 mV, 9 000 000 \mu V, ...$.

• This reminds me to tasks, that take 10 micro fortnights (from a programmer's view :-) Commented Apr 2, 2016 at 19:42