# T4 to T3 conversion ratio: Hey! I wanted to work... - Thyroid UK

Thyroid UK
103,895 members120,425 posts

Hey! I wanted to work out my ratio have complete brain fog on how to do it!

Can someone post the calculation or link to a Polish? Site

FT4 currently 22

FT3 currently 3.2

Also DI02 testing... Experiences of test and how receptive GP/endo is with result.

Many thanks

18 Replies

I think we need the ranges to work out the ratio.

Just out of curiosity, why do you want a link to a Polish site? Or is that a typo?

How does that work? I tried, but I don't speak Polish, so obviously got it wrong!

Marz
in reply to greygoose

You type in your FT4 result - followed by the bottom figure of the range - followed by the top ! Ditto for FT3 - then Press the blue button below - and hey presto the percentages appear !

greygoose
in reply to Marz

Oh brilliant! lol First time I've seen that.

Marz
in reply to greygoose

I have posted it before - possibly years ago !

greygoose
in reply to Marz

Oh, well, you know what my memory is like! lol Thanks, anyway.

Marz
in reply to greygoose

healthunlocked.com/thyroidu...

You may find the above discussion interesting

greygoose
in reply to Marz

Yes, very interesting! lol

Marz
in reply to greygoose

Bexg

You just divide FT4 by FT3 to get the ratio

22 divided by 3.2 = 6.875 : 1

Bexg
in reply to SeasideSusie

Oh yes!! 🤣🤣🤣 I remember now.

kiefer
in reply to SeasideSusie

What concentrations for FT4 and FT3 are you using for these calculations?

This only works if blood levels are re-calculated to comply with those fixed concentrations. Otherwise, the mathematical result won't fit into the same ratios that you use to determine a normal range of conversion.

My FT4 was 0.7 ng/mL

My FT3 was 3.2 pg/mL

0.7 divided by 3.2 = 0.21875 : 1

in reply to kiefer

Kiefer

You are in the US with different ranges and units than those we have in the UK so I can't, and don't, suggest that method for your results.

In the UK for both FT4 and FT3 it's pmol/L.

See if the calculator that Angelofthenorth linked to is any help for your results

chorobytarczycy.eu/kalkulator

kiefer
in reply to SeasideSusie

I already checked the link. It was on how to determine the percentage in normal range.

Perhaps you could direct me to where you obtained the T4 to T3 conversion ratio concept? I've done a lot of reading but it's always possible to completely miss important stuff.

The first time I "heard" about calculating a T4 to T3 conversion ratio was on this forum and it makes perfect sense to determine if T4 is being utilized effectively before just dogmatically raising the dose.

in reply to kiefer

Yes I understand that the calculator gives the percentage, it's still useful as it shows how far through a range the result is and you can see if they're in balance or whether there is a problem with conversion.

I don't know how to change the unit of measurement of FT4 to that of FT3 for your country's ranges, it's not something that I need to do, as I say I only give the information about dividing FT4 by FT3 when it's UK results. Have you tried Googling for a method?

The information about dividing FT4 by FT3 when units of measurement are the same was originally posted by member diogenes - Dr John Midgeley - who is an advisor to Thyroid UK