# mmol/L to mg/dl Conversion

**URL:** <https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911>\
**Category:** Share\
**Tags:** mmol, mgdl, conversion\
**Created:** [December 19, 2017, 10:16pm UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911 "2017-12-19T22:16:08Z")\
**Posts on this page:** 20\
**Page:** 4

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**Author:** ![NickR](https://avatars.discourse-cdn.com/v4/letter/n/dc4da7/32.png) [@NickR](https://forum.fudiabetes.org/u/NickR)\
**Post date:** [January 6, 2020, 2:23am UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/61 "2020-01-06T02:23:00Z")

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Actually it is mmol/L not mmo/L. Just sayin 🙂

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**Author:** ![Boerenkool](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/boerenkool/32/6307_2.png) [@Boerenkool](https://forum.fudiabetes.org/u/Boerenkool)\
**Post date:** [January 6, 2020, 8:37am UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/62 "2020-01-06T08:37:02Z")

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Thanks! I’ve changed the title. I’m quite surprised that I never spotted that typo.

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**Author:** ![NickR](https://avatars.discourse-cdn.com/v4/letter/n/dc4da7/32.png) [@NickR](https://forum.fudiabetes.org/u/NickR)\
**Post date:** [January 15, 2020, 4:55am UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/63 "2020-01-15T04:55:43Z")

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There are too many bloody L’s in it, and the / looks a bit like a lower case L too. Easy to scan and miss!

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**Author:** ![jbowler](https://avatars.discourse-cdn.com/v4/letter/j/e274bd/32.png) [@jbowler](https://forum.fudiabetes.org/u/jbowler)\
**Post date:** [January 30, 2020, 5:12am UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/64 "2020-01-30T05:12:22Z")

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> [@NickR](#):
>
> Actually it is mmol/L not mmo/L. Just sayin

I much prefer mM. Quite apart from the fact that I learned to spell litre with a lowercase ell when I was young (I would probably have failed if I said “L”) and quite apart from the fact that the use of multiple letters (“mol”) in a quantity that can be qualified (“mmol”) is pernicious (like, is it mmol, m-mol, mm-ol, or mmo-l?) [M](https://en.wikipedia.org/wiki/Molar_concentration) is the right letter.

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**Author:** ![Chris](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/chris/32/382_2.png) [@Chris](https://forum.fudiabetes.org/u/Chris)\
**Post date:** [January 30, 2020, 6:20am UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/65 "2020-01-30T06:20:06Z")

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All is right in the world if you just remember Avogadro’s number and the molecular weight of sugar. 6.22 x 10 to the 23rd power, and 342.3 grams per mole. Then all these conversions make perfect sense. Convert to your hearts content and figure out exactly how many molecules of sugar one unit of insulin covers.

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**Author:** ![jbowler](https://avatars.discourse-cdn.com/v4/letter/j/e274bd/32.png) [@jbowler](https://forum.fudiabetes.org/u/jbowler)\
**Post date:** [January 30, 2020, 6:31pm UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/66 "2020-01-30T18:31:53Z")

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Avogadro’s number factors out; that’s why it works to say “5mmol/L” - “mol” is just Avogadro’s number. I was certainly taught it around 1976 as part of high school chemistry, well, I was taught 6.023E23 but found a better approximation 6.022169E23+/-.00014E23 and I’ve remembered it since then. However I don’t think I have ever had to use it in a computation; this is why it just appears as “mol” in equations.

As a result the convertion factor just comes from the molecular weight of glucose. It is necessary to get it right of course, but a chemist will know the formula (C6H12O6 - six carbo “C” hydrate “H20” units) and remember the atomic weights (C-12g/mol, H - 1, O - 16) to get the molecular weight - 180g/mol). More likely these days just look it up on Google; 180.156g/mol.

Then the convertion factor from “thousandths of a mole of glucose per litre of blood” to “thousandths of a gramme of glucose per tenth of a litre of blood” is just:

`blood glucose in mM: bg mmol/L`  
`(milli)grammes glucose per litre: 180.156*bg mg/L` (See how the ‘mol’ disappears.)  
`milligrammes glucose per tenth of a litre: 18.0156*bg mg/dL`

I.e. the convertion factor is just the molecular weight of glucose divided by 10, which is kind of easy.

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**Author:** ![Eric](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/eric/32/9209_2.png) [@Eric](https://forum.fudiabetes.org/u/Eric)\
**Post date:** [January 30, 2020, 6:52pm UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/67 "2020-01-30T18:52:31Z")

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As always, FUD has the best reference material.

> [@mmol/L to mg/dl Conversion](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/22):
>
> There is actually a very easy way to do the conversion. The molecular formula for Glucose is C6H12O6. Of course everyone knows the periodic table, and the atomic mass for each element in a glucose molecule. carbon - 12.011 (x 6) hydrogen - 1.008 (x 12) oxygen - 15.999 (x 6) [image] So it is very easy to see that glucose (C6H12O6) has a molecular weight of 180.156 Converting moles to grams then becomes just as elementary as converting millimoles to moles, grams to milligrams, and liters to…

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**Author:** ![NickR](https://avatars.discourse-cdn.com/v4/letter/n/dc4da7/32.png) [@NickR](https://forum.fudiabetes.org/u/NickR)\
**Post date:** [January 31, 2020, 5:13am UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/68 "2020-01-31T05:13:58Z")

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In SI units, unit abbreviations only have an initial upper case if they are named after a real person. Hence A for amperes, V for volts, m for metres, N for newton, K for kelvin, s for second. Ampere, Volta, Newton and Kelvin were people. There was no Mr Metre or Ms Second.

Mole was not a person, so it cannot be M and m is already taken. If you want to change the SI system, it’ll take more than a post here 🙂

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**Author:** ![NickR](https://avatars.discourse-cdn.com/v4/letter/n/dc4da7/32.png) [@NickR](https://forum.fudiabetes.org/u/NickR)\
**Post date:** [January 31, 2020, 5:53am UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/69 "2020-01-31T05:53:40Z")

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Actually someone is going to point out that the abbreviation for litre is L. Oh well.

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**Author:** ![jbowler](https://avatars.discourse-cdn.com/v4/letter/j/e274bd/32.png) [@jbowler](https://forum.fudiabetes.org/u/jbowler)\
**Post date:** [January 31, 2020, 7:19am UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/70 "2020-01-31T07:19:57Z")

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> [@NickR](#):
>
> Mole was not a person, so it cannot be M and m is already taken.

Despite the [reference](https://en.wikipedia.org/wiki/Molar_concentration) I gave?

Note that I was referring to the whole unit “mol/L” - “M” is the unit symbol for “molar”, a measure of the concentration of a substance expressed as a molarity; the number of moles in a litre of water. I admit, when I was 16 and learnt all this I did have a set of peculiar images form in my mind which tended to disrupt my ability to pay attention in the classroom so I may have missed something.

> [@NickR](#):
>
> In SI units, unit abbreviations only have an initial upper case if they are named after a real person.

Technically neither the use of molar for concentrations nor the use of litre for volumes are SI units but in fact chemists have been using them since the adoption of the SI. So they don’t obey the rules 😛. “mol” is an SI ‘unit’ (it is, in fact, just a count, so ‘unit’ is a bit misleading). The SI unit of volume is the cubic metre, so the unit of concentration is mol/m^3, which, ironically, is actually the unit we are using for blood glucose; 1mol/m^3 is 1mmol/L!

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**Author:** ![NickR](https://avatars.discourse-cdn.com/v4/letter/n/dc4da7/32.png) [@NickR](https://forum.fudiabetes.org/u/NickR)\
**Post date:** [January 31, 2020, 7:28am UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/71 "2020-01-31T07:28:15Z")

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Your memory of High School Chemistry is clearly better than mine LOL.

By the way, looking at your profile, very similar history. Me: juvenile onset at 13 (1975). Drinker. You’re clearly lighter and fitter though 🙂

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**Author:** ![Mike2.718281828](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/mike2.718281828/32/8117_2.png) [@Mike2.718281828](https://forum.fudiabetes.org/u/Mike2.718281828)\
**Post date:** [February 11, 2020, 8:57pm UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/72 "2020-02-11T20:57:43Z")

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Sam, you are correct about the 1/18 ratio. That ratio follows from the fact that the molar mass of glucose is 180.156g/mol. That, and a touch of stoichiometry. 😀

BTW, I’m new here. I was diagnosed on New Years Eve after 6 harrowing hours in the ER.

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**Author:** ![Mike2.718281828](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/mike2.718281828/32/8117_2.png) [@Mike2.718281828](https://forum.fudiabetes.org/u/Mike2.718281828)\
**Post date:** [February 11, 2020, 8:58pm UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/73 "2020-02-11T20:58:59Z")

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Wow… I should have read the whole thread… Oops.

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<div class="post-metadata">

**Author:** ![Chris](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/chris/32/382_2.png) [@Chris](https://forum.fudiabetes.org/u/Chris)\
**Post date:** [February 11, 2020, 9:39pm UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/74 "2020-02-11T21:39:13Z")

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Don’t feel bad @Mike2.718281828, we are a goofy and pretty scientific lot so high brow humor is always appreciated, if not always understood 😉

Looking forward to your contributions.

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**Author:** ![Mike2.718281828](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/mike2.718281828/32/8117_2.png) [@Mike2.718281828](https://forum.fudiabetes.org/u/Mike2.718281828)\
**Post date:** [February 12, 2020, 2:46pm UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/75 "2020-02-12T14:46:36Z")

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Thanks, Chris. The forum is full of informative discussion.

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**Author:** ![Kels\_eh](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/kels_eh/32/7629_2.png) [@Kels\_eh](https://forum.fudiabetes.org/u/Kels_eh)\
**Post date:** [February 22, 2020, 6:24am UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/76 "2020-02-22T06:24:00Z")

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This is awesome! Thanks for sharing.

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**Author:** ![Beacher](https://avatars.discourse-cdn.com/v4/letter/b/a6a055/32.png) [@Beacher](https://forum.fudiabetes.org/u/Beacher)\
**Post date:** [February 22, 2020, 1:59pm UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/77 "2020-02-22T13:59:49Z")

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> [@NickR](#):
>
> Actually someone is going to point out that the abbreviation for litre is L.

The litre, along with metric ton, degree, hectare and a few others, is not an official SI unit but is widely used enough to be accepted within the system, so it doesn’t have to follow the rules. By convention, capital L is used to prevent confusion with the numeral 1 or, in many fonts, uppercase I (eye) or lowercase l (ell). (See what I mean?) Capital L is universal in Canada, but in Europe the lowercase is common; on food packaging it’s often a script (ℓ) so it’s easily distinguished.

Yours sincerely,  
Mr. Trivia

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**Author:** ![kmichel](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/kmichel/32/3085_2.png) [@kmichel](https://forum.fudiabetes.org/u/kmichel)\
**Post date:** [March 3, 2020, 9:34pm UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/78 "2020-03-03T21:34:34Z")

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> [@NickR](#):
>
> > [@NickR](#):
> >
> > Actually someone is going to point out that the abbreviation for litre is L.
> 
> The litre, along with metric ton

And, of course, us darn Americans will insist it is Liter instead of Litre… 😛

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<div class="post-metadata">

**Author:** ![jbowler](https://avatars.discourse-cdn.com/v4/letter/j/e274bd/32.png) [@jbowler](https://forum.fudiabetes.org/u/jbowler)\
**Post date:** [March 4, 2020, 3:35am UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/79 "2020-03-04T03:35:46Z")

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> [@kmichel](#):
>
> Americans will insist it is Liter instead of Litre

If you wish. As an American I don’t want to make life difficult for myself, therefore this publication:

> **[Writing with SI (Metric System) Units](https://www.nist.gov/pml/owm/writing-si-metric-system-units)**
>
> As of August 16, 2023 the physics.nist.gov historic SI Units site has permanently retired.

is in my round filing cabinet.

Somewhere, way back, there is a set of rules in the Federal Register which covers the variant spellings adopted in the US post-Webster. It basically tells Webster what he should do with his whatever. I can’t find the right link, however I did find this from 1977:

> **[Federal Register](https://books.google.com/books?id=JjY4AQAAMAAJ&ppis=_e&lpg=PA16398&ots=sBSHK4l1-W&dq=federal%20publication%20spelling%20requirements&pg=PA17117#v=snippet&q=metre&f=false)**

Pretty much we are retrograde; we’re just making ourselves different from the rest of the world out of arrogance, I guess.

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<div class="post-metadata">

**Author:** ![Lizzyb](https://avatars.discourse-cdn.com/v4/letter/l/a4c791/32.png) [@Lizzyb](https://forum.fudiabetes.org/u/Lizzyb)\
**Post date:** [September 4, 2020, 6:13am UTC](https://forum.fudiabetes.org/t/mmol-l-to-mg-dl-conversion/2911/80 "2020-09-04T06:13:17Z")

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And your Australian and NZ ones too! @Eric

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