I've used http://aging.ai/ v3 and https://bioagecalc.azurewebsites.net/ to check out my biological age.
I'm 35-years-old (36 in October).
Aging.ai put me at 23-years-old (this is as low as it can predict as the data is cut off at 23).
AgelessR puts me at phenotypic age of 14.94 to 22.94 years-old.
Unfortunately, they don't test RDW here in the UK as standard practice, but as long as I put it within the normal range, it comes out somewhere between that range.
People keep saying I should get a DNA Methylation test, so I'm looking at that after I get get my genome sequenced and a new round of blood tests.
Got similar trend w/ aging.ai, it looks typical (I mean in my case and from other "biohackers" i read about) the nos. turn out lower and I wonder why. Wrt RDW, as RDW = SD-MCV / MCV (SD-MCV is the standard deviation of the distribution of red cell volumes, MCV) I will ask my lab. Maybe the machine will also calculate the RDW % but is not reported, for some reason, to the clinician. I know a competing lab in my region reporting both RDW and MCV though, so it must be possible. I use values I got in US, in the normal range. However, e.g. Levine's clock I discussed previously in this thread is quite sensitive to that value. Have you tried Levine's Phenotypic Age calculator? Please let us know and ask also you lab, it is very interesting.... Thank you.