How well your body is converting the storage thyroid hormone into the active one. TSH says nothing about this.
| Result | Band |
|---|---|
| Under 2.0 | Lower than usual |
| 2.0 to 4.0 | Typical |
| Above 4.0 | Higher than usual |
⚠️ There is no formally standardised reference range for this ratio, and the bands above depend on your laboratory's units. Treat it as context, not as a result.
BloodMarker reads your whole panel and tells you what the lines say together, which is the part no single calculation can do.
Your values carry over · PDF or a photo · about 8 seconds
It reflects the conversion of T4 into the more active T3. A low ratio is sometimes discussed in the context of poor conversion.
Very much. This calculator assumes Free T3 in pg/mL and Free T4 in ng/dL. Other unit combinations give a completely different number.
Not medical advice. These calculators are for information only. Reference bands differ between laboratories and none of these numbers can be interpreted without your history, your other results and a clinician. Nothing you type here is sent to us or stored on a server.