Vitamin C Requirement Calculator

About this calculator

The Recommended Dietary Allowance (RDA) for vitamin C, set by the US Institute of Medicine (now the National Academy of Medicine), is 90 mg per day for adult men and 75 mg per day for adult women — figures based on the intake needed to maintain near-maximal white blood cell concentration of the vitamin with a margin of safety, not merely the amount needed to prevent scurvy.

Smokers have a distinctly higher requirement: the same guidelines add 35 mg per day on top of the baseline recommendation, because tobacco smoke increases oxidative stress and accelerates the metabolic turnover of vitamin C in the body, meaning smokers need meaningfully more dietary intake just to reach the same blood levels as non-smokers.

This calculator applies these age-, sex-, and smoking-status-specific NIH/Institute of Medicine recommendations to give you your personal daily vitamin C target.