Iron Supplement Calculator

This calculator sizes an iron regimen: how much elemental iron per day, how many tablets that implies, and how long to stay on it. Deficiency Level is the dominant input — it sets the daily target at 60 mg for mild, 120 for moderate, or 200 for severe deficiency, and independently fixes Treatment Duration at 8, 12, or 16 weeks. Body Weight scales the daily target linearly around a 70 kg reference: at 105 kg the moderate target becomes 180 mg, at 35 kg it halves to 60. Supplement Type never changes the elemental target — instead it sets how much of each tablet is actually iron (ferrous sulfate 20 percent, gluconate 12, fumarate 33) and therefore the tablet yield used for Tablets per Day: a standard tablet delivers 65 mg of elemental iron as sulfate, 39 as gluconate, or 107 as fumarate.

That is why the same 120 mg target reads as two sulfate tablets, four gluconate, or two fumarate — gluconate's low density is what makes it the multi-tablet option, and fumarate's density is why heavy dosing stays pill-light. The tablet count is always rounded up with a floor of one, so partial tablets are never prescribed. One limitation worth flagging: the body-weight scaling has no upper clamp, so at the high end of the weight range (200 kg) combined with severe deficiency, the model projects an elemental iron target above 500 mg/day — this is a linear model, not a clinical ceiling, and very high body weights can produce doses well above typical clinical guidance. Not modeled: alternate-day dosing absorption research, vitamin C co-administration, or ferritin-based titration.