Iron Deficiency Calculator

The calculation relies on established hematological formulas to determine how much supplemental iron is required to restore normal hemoglobin levels and replenish body storage iron (ferritin). The primary formula is expressed as: Deficit = Weight (kg) × (Hgb target - Hgb actual) × 2.4 + Iron stores. In this equation, the constant 2.4 accounts for the iron content of hemoglobin and blood volume expansion. Additionally, Iron stores are estimated as a fixed replacement pool, typically capped at a maximum of 500 mg or calculated as 15 mg per kilogram of body weight, whichever is smaller, to ensure safe replenishment limits.

Consider an adult patient weighing 70 kg who presents with an actual hemoglobin level (Hgb actual) of 10 g/dL, while their target hemoglobin level (Hgb target) is set at 14 g/dL. First, calculate the hemoglobin deficit factor: 70 kg × (14 - 10) × 2.4 = 70 × 4 × 2.4 = 672 mg. Next, determine the baseline iron stores allowance: the minimum of 500 mg or (70 kg × 15 mg/kg = 1050 mg), which equals 500 mg. Finally, sum these values to find the total iron deficit: 672 mg + 500 mg = 1,172 mg of total iron required for complete repletion.

Always consult a licensed medical provider before starting any high-dose iron therapy, as excessive iron accumulation can lead to toxicity. Ensure your bloodwork is current and accurately reflects your true hemoglobin state before inputting values into the calculator. Pair oral iron supplements with vitamin C to enhance absorption, but separate them from calcium, coffee, or tea which can inhibit uptake.