Transferrin saturation calculator and normal range
Short answer: Transferrin saturation is serum iron divided by TIBC (total iron binding capacity), times 100: how full the blood’s iron carrier is. About 20 to 45% is normal. Below 20% points to too little iron reaching the cells; 45% or above is the usual reason to check for iron overload.
Free calculator
Transferrin saturation calculator
Transferrin saturation (%) = serum iron ÷ TIBC × 100
Sources: Gattermann N, Muckenthaler MU, Kulozik AE, Metzgeroth G, Hastka J. The evaluation of iron deficiency and iron overload. Dtsch Arztebl Int 2021;118(49):847-856.
Sometimes printed as "Iron" or "Fe"
If your report prints UIBC instead, TIBC = iron + UIBC
Your result
Enter the numbers from your lab report to see your result.
Iron swings through the day and after meals or supplements, so a morning sample after an overnight fast, with no iron tablets for 24 hours, gives the most reliable result.
Worked out in your browser. Nothing you type is sent or saved.
A pointer, not a diagnosis. Talk to a doctor about your result, and sooner if you feel unwell.
How to read the result
- Low (below 20%)< 20%Less iron is reaching the cells that need it. With a low ferritin this is iron deficiency; with a normal or high ferritin it is more often inflammation holding iron back. Iron deficiency always has a cause worth finding, so talk to a doctor rather than only taking iron.
- Normal (20 to 44%)20 – 45%Your transferrin saturation is in the usual range.
- High (45% or above)≥ 45%More iron than usual is loaded onto transferrin. A recent iron tablet or meal can do it, so the first step is a repeat on a fasting morning sample with ferritin. If it stays high, doctors check for haemochromatosis (inherited iron overload), which is common and treatable.
Your lab’s range
The range on the HealthOS iron page is 20–45%. Labs print slightly different ones, often about 15–50% or 20–50%, and some use a different upper limit for men and women. Your lab’s range comes first, and ferritin is read alongside.
How it is worked out
Transferrin saturation (%) = serum iron ÷ TIBC × 100
Iron swings through the day and after meals or supplements, so a morning sample after an overnight fast, with no iron tablets for 24 hours, gives the most reliable result.
Sources
- Gattermann N, Muckenthaler MU, Kulozik AE, Metzgeroth G, Hastka J. The evaluation of iron deficiency and iron overload. Dtsch Arztebl Int 2021;118(49):847-856.
- Bacon BR, Adams PC, Kowdley KV, Powell LW, Tavill AS. Diagnosis and management of hemochromatosis: 2011 practice guideline by the American Association for the Study of Liver Diseases. Hepatology 2011;54(1):328-343.
- European Association for the Study of the Liver. EASL Clinical Practice Guidelines on haemochromatosis. J Hepatol 2022;77(2):479-502.
The markers it uses
Questions
- What is a normal transferrin saturation?
- About 20 to 45%, though lab ranges differ a little. Below 20% suggests iron deficiency or iron held back by inflammation; ferritin tells them apart. 45% or above on a fasting sample is the usual trigger to test for haemochromatosis.
- How do you calculate transferrin saturation?
- Divide serum iron by TIBC (both in the same unit, µg/dL or µmol/L) and multiply by 100. Iron 90 µg/dL with TIBC 330 µg/dL gives 27%. If your report prints UIBC instead of TIBC, add iron and UIBC to get TIBC.
- What does a high transferrin saturation mean?
- Often only a recent iron tablet or iron-rich meal. If it is 45% or above on a fasting morning sample, doctors check ferritin and the HFE gene for haemochromatosis. European guidance uses above 45% in women and above 50% in men, together with a raised ferritin.
- Is transferrin saturation the same as ferritin?
- No. Ferritin shows your iron stores; transferrin saturation shows how much iron is in circulation right now. Doctors read the two together.
A pointer, not a diagnosis. Talk to a doctor about your result, and sooner if you feel unwell. Reference ranges are general-population guidance compiled from common clinical laboratories, not a diagnosis. Lab-to-lab ranges differ. Always read your results with your doctor.