Iron Intake Calculator
Daily iron target by age, sex and diet type.
Enter your values
ⓘ Live results
Results
- Daily iron target
- 18 mg
- Base RDA
- 18 mg
- Diet adjustment
- 1x
- Upper limit
- 45 mg/day for adults
Quick answer
Iron needs vary widely: 8 mg for adult men, 18 mg for menstruating women, and up to 1.8x more on a plant-based diet.
target = base RDA x diet factor
How to use the Iron Intake Calculator
- 1Pick the group that matches your age and life stage.
- 2Select your diet type — plant iron is absorbed far less efficiently.
- 3Pair iron-rich foods with vitamin C to boost absorption.
Worked example
Using the values the calculator loads with:
Inputs
- GroupMenstruating female
- DietIncludes meat
Results
- Daily iron target18 mg
- Base RDA18 mg
- Diet adjustment1x
- Upper limit45 mg/day for adults
Frequently asked questions
Why do vegetarians need more?
Non-haem iron from plants is absorbed at roughly half the rate of haem iron from meat.
Should I supplement?
Only after a blood test — excess iron accumulates and is harmful.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.