Iron deficit calculator (Ganzoni)
Estimates the total iron need from weight, haemoglobin and a target haemoglobin with the Ganzoni equation (1970). It shows the part for the haemoglobin deficit and the part for iron stores.
- Body size and dosing
- Ganzoni 1970
- Runs on your device
Short answer
The Ganzoni equation (1970) estimates the total iron deficit in mg as weight (kg) × (target haemoglobin − haemoglobin) (g/dL) × 2.4, plus iron stores of 500 mg (15 mg/kg under 35 kg).
Iron deficit (Ganzoni)
Runs on your device. Nothing you enter is saved or sent.
Estimate only. Interpret it with the patient's clinical picture and the product label.
Sources
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- Ganzoni AM. Intravenous iron-dextran: therapeutic and experimental possibilities. Schweiz Med Wochenschr. 1970;100(7):301–303. PubMed 5413918
Formula version: Iron deficit (Ganzoni 1970) · MediHelp calc v1.3.1
Formula and sources checked on 2026-11-02
When this estimate is not valid
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- The Ganzoni equation estimates the total iron need. Several product labels use their own dosing tables, which take precedence.
- It does not give a dose per infusion or the number of visits; use the maximum single dose of the product.
- It does not include ongoing blood loss.
- Find and treat the cause of iron deficiency, and confirm it with ferritin and transferrin saturation.
Estimate only. Interpret it with the patient's clinical picture and the product label.
About this calculator
- What it is
- The Ganzoni equation estimates the total iron deficit from weight, current and target haemoglobin and an allowance for iron stores.
- Why it is used
- It sizes a course of intravenous iron in iron-deficiency anaemia.
- How to use it
- Enter weight, current haemoglobin and the target (default 15 g/dL as in the original equation, or the product's target); the stores allowance is 500 mg (some products use 15 mg/kg under 35 kg).
- How to read the result
- The result is the total elemental iron in mg to replace, not a dose per infusion; product labels have their own dosing tables and maximum single doses, which take precedence. It does not account for ongoing blood loss.
How it is calculated
Iron deficit (mg) = weight (kg) × (target Hb − Hb) (g/dL) × 2.4 + iron stores
The haemoglobin part is the weight multiplied by the gap between the target and the measured haemoglobin and by 2.4. Iron stores are added to it.
stores 500 mg (≥ 35 kg) or 15 mg/kg (< 35 kg)
Iron stores are 500 mg for a weight of 35 kg or more and 15 mg per kg below 35 kg.
default target Hb 15 g/dL (≥ 35 kg) or 13 g/dL (< 35 kg)
The target haemoglobin is optional: 15 g/dL if the weight is 35 kg or more and 13 g/dL below 35 kg. You can enter another target between 8 and 18 g/dL.
If the haemoglobin is at or above the target, the equation gives no iron deficit and the calculator says so. Haemoglobin in g/L is divided by 10 to give g/dL and weight in pounds is converted to kilograms.
Limits: weight 3–300 kg and haemoglobin 2–18 g/dL. The result is shown in mg, rounded to a whole number, with each step.
Worked example
A patient weighing 70 kg with a haemoglobin of 8 g/dL and the default target of 15 g/dL:
70 × (15 − 8) × 2.4 = 1176 mg500 mg1176 + 500 = 1676 mg
Total iron deficit 1676 mg: 1176 mg for the haemoglobin deficit and 500 mg for iron stores.
Questions
Is the result a dose to prescribe?
No. The Ganzoni equation estimates the total iron need. Several product labels use their own dosing tables, which take precedence.
Does it give the amount per infusion or the number of visits?
No. It does not give an amount per infusion or the number of visits; use the maximum single dose of the product.
Does it include ongoing blood loss?
No. It does not include ongoing blood loss.
Does it replace looking for the cause of iron deficiency?
No. The cause of iron deficiency should be found and treated, and the deficiency confirmed with ferritin and transferrin saturation.
Use the calculators in the MediHelp app
Estimate only. Interpret it with the patient's clinical picture and the product label.
