What is the normal transferrin saturation?

In adults, roughly 20–45%. In women the lower bound is lower (around 15%). Below 20% suggests iron deficiency, above 45–50% possible iron overload.

How do I calculate transferrin saturation?

TSAT = serum iron ÷ TIBC × 100%. If TIBC is unknown, it’s estimated from transferrin (TIBC ≈ transferrin g/L × 25.1). The calculator computes it from your values in µmol/L or µg/dL.

What does low transferrin saturation mean?

Saturation below 20% points to a lack of iron. Together with low ferritin it confirms iron deficiency. A doctor determines the cause (blood loss, diet, absorption) and treatment.

Is high transferrin saturation dangerous?

Persistently high saturation (above 45–50%) may mean iron overload; with high ferritin it warrants ruling out hemochromatosis. A one-off rise can follow iron supplements.

How is TSAT different from ferritin?

Ferritin reflects iron stores, while transferrin saturation shows how much iron is currently in transport. They’re read together: e.g., low ferritin + low TSAT is clear iron deficiency.

Transferrin saturation (TSAT): calculator and norm

Transferrin saturation (TSAT) = serum iron ÷ TIBC × 100%. Enter iron and TIBC — the calculator computes TSAT and compares it with the norm. Don’t have TIBC? Enter transferrin and we’ll convert it. Iron is accepted in µmol/L or µg/dL. Low saturation points to iron deficiency, high to iron overload.

Calculate transferrin saturation

Enter iron and TIBC (or transferrin) — the result appears instantly.

Transferrin saturation norm

Guidance for adults; in women the lower bound is lower (around 15%). Assess it together with ferritin and TIBC, not in isolation.

Transferrin saturation	Assessment
below 20%	Low — likely iron deficiency
20–45%	Normal
45–50%	Borderline high
above 50%	High — possible iron overload

What transferrin saturation is and how it’s computed

Transferrin is the protein that carries iron in the blood. Transferrin saturation (TSAT) shows how much of it is actually occupied by iron: TSAT = iron ÷ total iron-binding capacity (TIBC) × 100%.

If TIBC isn’t in the report, it can be estimated from transferrin: TIBC (µmol/L) ≈ transferrin (g/L) × 25.1. The calculator does this automatically and accepts iron in both µmol/L and µg/dL.

Low saturation: iron deficiency

TSAT below 20% is a typical sign of iron deficiency: there isn’t enough iron to fill transferrin. Together with low ferritin it confirms iron deficiency even before anemia.

Causes include blood loss (including heavy periods), low dietary iron, malabsorption and pregnancy. A doctor should investigate and prescribe iron based on the whole panel, not TSAT alone.

High saturation: iron overload

TSAT above 45–50% may indicate iron overload. Persistently high saturation (especially above 50% with high ferritin) is a reason to rule out hereditary hemochromatosis and other causes of iron excess.

A one-off high TSAT can follow iron supplements or an iron-rich meal. A doctor assesses it from repeat fasting tests and ferritin.

Frequently asked questions

In adults, roughly 20–45%. In women the lower bound is lower (around 15%). Below 20% suggests iron deficiency, above 45–50% possible iron overload.
TSAT = serum iron ÷ TIBC × 100%. If TIBC is unknown, it’s estimated from transferrin (TIBC ≈ transferrin g/L × 25.1). The calculator computes it from your values in µmol/L or µg/dL.
Saturation below 20% points to a lack of iron. Together with low ferritin it confirms iron deficiency. A doctor determines the cause (blood loss, diet, absorption) and treatment.
Persistently high saturation (above 45–50%) may mean iron overload; with high ferritin it warrants ruling out hemochromatosis. A one-off rise can follow iron supplements.
Ferritin reflects iron stores, while transferrin saturation shows how much iron is currently in transport. They’re read together: e.g., low ferritin + low TSAT is clear iron deficiency.

Decode your iron panel

Upload your blood test — AI cross-checks iron, ferritin, TIBC and transferrin and explains clearly whether there’s a deficiency or overload.

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This calculator is for reference and information only and is not a diagnosis. Iron deficiency or overload is determined by a doctor from the full panel of markers.