Transferrin Saturation Calculator
Enter the serum iron and TIBC printed on your blood test and pick the unit they were reported in. Get transferrin saturation as a percentage, both values echoed in the other unit, and where the percentage falls against the published adult reference range.
Transferrin saturation
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Transferrin saturation
— %
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- Serum iron
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- TIBC
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- Reference range
- 20–50%
Ranges vary by laboratory. Use the range printed on your own report. Lab results are interpreted by a clinician alongside the full panel and your history.
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How transferrin saturation is calculated
A total iron binding capacity (TIBC) blood test measures how much iron the blood could carry, mostly on the transport protein transferrin. Serum iron is how much is being carried right now, and transferrin saturation (TSAT) is the fraction of that capacity in use: serum iron divided by TIBC, multiplied by 100.
Both values on a report are printed in the same unit, and because the calculation is a ratio the unit cancels. 100 µg/dL over 350 µg/dL and 17.9 µmol/L over 62.65 µmol/L both come to 28.6%, so there is nothing to convert before working out the percentage. The conversion is here only for reading a report printed in the unit you are less used to: µg/dL × 0.179 = µmol/L, and µmol/L ÷ 0.179 = µg/dL.
The commonly published adult reference range for transferrin saturation is 20–50%, alongside roughly 60–170 µg/dL for serum iron and 240–450 µg/dL for TIBC. Laboratories set ranges from their own assay and population, so the range printed on your own report is the one that applies to your result.
TSAT (%) = (serum iron ÷ TIBC) × 100 This is arithmetic on numbers you already have, not a diagnosis. It does not name a condition, and it does not recommend iron supplements or any other treatment. A percentage inside or outside a reference range is not a conclusion on its own — lab results are interpreted by a clinician alongside the full panel and your own history.
MedlinePlus: Iron Tests ↗NIH Office of Dietary Supplements: Iron ↗
TIBC and transferrin saturation FAQ
What does a total iron binding capacity blood test measure?
TIBC measures how much iron the blood could carry, mostly on transferrin. It is a capacity rather than an amount: serum iron is what is being carried at the moment of the draw, and transferrin saturation expresses that amount as a share of the capacity.
Does the unit change the transferrin saturation percentage?
No. TSAT is serum iron divided by TIBC, so as long as both values use the same unit the unit cancels and the percentage is identical in µg/dL and µmol/L. The calculator still echoes both numbers in the other unit, using µg/dL × 0.179 = µmol/L, in case your report and your reference sheet disagree.
How does transferrin saturation relate to ferritin?
They describe different things. TSAT is the share of the blood's iron carrying capacity in use at the time of the draw, while ferritin reflects stored iron. Iron panels usually report both, and a clinician reads them together with the rest of the results rather than one at a time.
Why does my lab print a different reference range?
Each laboratory derives its ranges from its own assay method and the population it tests, so a printed range can differ from the 20–50% figure widely published for adults. Ranges can also vary with age, sex and the time of day the sample was taken. Use the range on your own report.
Are my values saved?
No. The calculation runs in your browser and the values you enter are not saved by this tool.