Total Iron-Binding Capacity Calculator

About this calculator

Total iron-binding capacity (TIBC) measures the blood’s total capacity to bind iron via transferrin, and can be calculated two ways: as serum iron plus UIBC (unsaturated iron-binding capacity, the unused portion measured directly by the lab), or estimated from a transferrin level using the approximation TIBC ≈ transferrin (mg/dL) × 1.43.

Dividing serum iron by TIBC gives transferrin saturation, the percentage of binding sites actually occupied by iron — the single most useful number on an iron panel for telling conditions apart. Low saturation (typically under 15–20%) points toward iron-deficiency anemia, while high saturation (often above 45%) is a hallmark of hereditary hemochromatosis or other iron-overload states; anemia of chronic disease, by contrast, often shows a low or normal TIBC alongside low serum iron, the opposite pattern from deficiency.

This calculator takes your serum iron plus either UIBC or transferrin and returns TIBC along with the transferrin saturation percentage.