Transferrin Saturation Calculator

Reviewed by the CalculatorHub team, edited by James Graham. TSAT from serum iron and total iron-binding capacity. Last verified 19 June 2026.

Transferrin saturation (TSAT) is the percentage of transferrin, the iron-transport protein, that is bound to iron. It is calculated from serum iron and total iron-binding capacity (TIBC) and is used in evaluating iron deficiency and iron overload. A low TSAT supports iron deficiency, while a high TSAT can indicate iron overload such as hemochromatosis. This tool computes the ratio; interpretation belongs to a clinician.

Serum iron (mcg/dL)

Total iron-binding capacity (mcg/dL)

Transferrin saturation (%)

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Transferrin saturation formula

TSAT (%) = 100 * serum iron / total iron-binding capacity

Serum iron and TIBC are both in micrograms per decilitre (mcg/dL), so the units cancel and the result is a percentage. The same ratio holds if both are entered in micromoles per litre instead.

Worked example

For serum iron 60 mcg/dL and TIBC 300 mcg/dL: TSAT = 100 * 60 / 300 = 20.00%. Reference ranges vary, but a value around 20% is often near the lower end of normal for adults.

Frequently asked questions

What is a normal transferrin saturation?

Reference ranges differ by laboratory and are not built into this tool. Many labs report roughly 20% to 50% as normal for adults, with lower values suggesting iron deficiency and values above about 45% to 50% prompting evaluation for iron overload. Use your own lab's reference range.

What is TIBC?

Total iron-binding capacity measures the blood's capacity to bind iron with transferrin. It reflects the amount of transferrin available. TSAT relates the iron actually bound to this total capacity.

Why use TSAT instead of serum iron alone?

Serum iron varies through the day and with recent intake. Expressing iron as a fraction of binding capacity gives a more stable indicator of iron status than serum iron by itself.

Is this a diagnosis?

No. It computes a ratio from values you enter and does not diagnose iron deficiency or overload. Interpretation requires a clinician and usually additional tests such as ferritin.

Sources

U.S. National Library of Medicine, MedlinePlus: Transferrin Test.
U.S. National Heart, Lung, and Blood Institute: Iron-Deficiency Anemia.

Reviewed by the CalculatorHub team, edited by James Graham, 19 June 2026. Educational tool, not medical advice. See our methodology.