What is a normal free T4 level?
The short answer
A typical US lab prints a normal free T4 range of 0.8–1.8 ng/dL. That range exists to catch disease, not to describe your best.
Nobody we follow has said what your Free T4 should be. It comes up on the shows, but never with a number.
What Free T4 measures
The unbound form of the main hormone your thyroid releases.
Your body converts it into the active form, so it shows what the thyroid is putting out before conversion.
Checked against MedlinePlus — Thyroxine (T4) Test.
Common questions
What is a normal Free T4 level?
Most US labs print 0.8–1.8 ng/dL. Your report grades you against that range. It exists to catch disease, not to describe your best.
What does your Free T4 number mean?
On a typical lab range, under 0.8 ng/dL is low, 0.8 to 1.8 is normal and over 1.8 is high. Your own report prints its range next to your number, and that is the one your lab uses. Nobody we follow has drawn a line inside that range.
What does the Free T4 test measure?
The unbound form of the main hormone your thyroid releases. Your body converts it into the active form, so it shows what the thyroid is putting out before conversion.
Why is there no target here?
Because nobody we follow has named a number for Free T4. If that changes, it will be here.