Personally I get confused by the old measure of "grains". To me it's like rods. poles or perches. So I use this table if ayone's interested
What is 1 grain equal to in grams?
Grains to Grams table
Grains1 Grams 0.06
Grains 2 Grams 0.13
Grains 3 Grams 0.19
Grains 4 Grams 0.26
Your post has made me think of vitamin D3 - why is it measured as IU when other things are measured in mg or mcg? I’ve never figured that one out.
diogenes has posted a nice and simple conversion.
My vade mecum has a chapter on units.
Including:
International Units
Some substances are measured by how much effect they have rather than absolute amount in terms of weight or volume. This is often expressed using the International Unit which is often referred to simply as Unit. The standard abbreviation is IU – though often simply U.
Very often, International Units were created before anyone knew what substance was having the effect. International Units are always strictly related to single substances. There is absolutely NO relationship between, say, an IU of vitamin D and an IU of vitamin A.
For vitamin D, one microgram is 40 international units.
Whereas for vitamin A it varies greatly depending on which form of vitamin A you are talking about.
International Units are also used for some blood tests such as TSH concentration which is in milli-International Units per litre (abbreviated as mIU/L or mU/L).
And a section on grains which is both more comprehensive and more complicated than most of us need.
Grains
A traditional measurement of medicine was the grain which was based on one grain of barley. The grain continues to be used for desiccated thyroid. Some brands use the traditional grain which is very close to 65 milligrams. Sometimes we see use of an approximation of 60 milligrams which makes the numbers simpler.
The abbreviation for grain is gr but it is usually better to write grain in full to help avoid mistakes. (It is often confused with g for gram).
The grain is a part of both the British and US Apothecaries measurement systems. Other units occasionally mentioned include gill, ounce, drachm/dram, scruple, grain, minim. (These units may not be identical in both systems.)
helvella - Vade Mecum for Thyroid
The term vade mecum means:
1. A referential book such as a handbook or manual.
2. A useful object, constantly carried on one’s person.
Please don't get put off by the number of pages!
Nor by the fact it is targeted at people interested in thyroid issues. Much of its contents could be of use to many involved in health issues. Things like abbreviations, lists, general reference information, an Appendix of links to many useful websites.
And do keep up to date. I edit it frequently- sometimes trivially, sometimes extensively. If your copy is more than a few weeks old, please download it again. (You must download - not just view in a browser- for the Table of Contents to work.)
In particular, it is not intended that you sit and read the document. Just that you download it and know you can look things up.
If there is anything you'd like me to add, let me know.
From Dropbox:
dropbox.com/s/vp5ct1cwc03bl...
From Google Drive:
drive.google.com/file/d/1P9...
Thank you helvella, I know it’s been said many times before but you are a treasure and what would we do without you 😊
Fruitandnutcase
Some D3 supplements are shown as ug/mcg (never mg), some are shown as iu and some are shown as both.
25mcg = 1,000iu
I believe iu is the older unit of measurement and mcg is the updated one.
I prefer iu, for some reason my brain copes better with that than mcg, I instantly recognise it whereas if it's shown in mcg I have to work it out in iu (probably because I'm old!)
This converter to convert mcg to IU or vice versa might be helpful, although I realise that isn't what you are asking :
grassrootshealth.net/projec...
This might answer your question :
Thank you....but for me it's still confusing. I've been prescribed NDT 1 x 30 mg......is that 1 grain? 1/2 grain? I get lost with grains.
That sounds like half a grain and probably the brand Efra :
1 grain Efra is 60mg and detailed as containing 8 mcg of T3 + 35 mcg of T4 :
so your 1/2 grain contains 4 mccg T3 + 17.50 mcg T4 :
Thank you pennyannie. Spot on with Erfa.
Sort of info to print on the back of a school jotter, Diogenes!
Don’t take NDT but I’m curious. Why isn’t two grains 0.12 and 4 grains 25
Because a grain isn't exactly 0.06.
It is actually just under 0.065.
Usual rounding rules makes that 0.06.
Twice 0.065 is 0.130 and, again, usual rounding rules make that 0.13.
And so on.
Ah, got it. Thank you
Just did this little table using exact conversions 
The simple approach suggested by diogenes is fine most of the time.
Hi helvella is there a place that I can find a list of different medications and their cost to the NHS?
Yes!
NHS Drug Tariff (Scotland a bit different, NI - I've never worked out)
nhsbsa.nhs.uk/pharmacies-gp...
Open the tariff and search for what you want.
How DO you do that hellvella?!!
How do I do what?
Create the spreadsheet? Post an image?
I made this for Armour if anyone wants it:
Doses (grains) advice after thyroidectomy
Nutrient absorption- coffee, grains and alcohol 
