Daily Vitamin C Intake Calculator
NIH-recommended daily vitamin C intake by age, sex, and smoking status.
A general population guideline (NIH RDA), not medical advice — very high-dose vitamin C supplementation can cause digestive upset in some people.
Recommended daily vitamin C
75 mg
NIH RDA guideline
For informational and educational purposes only — not medical advice, and not a substitute for consulting a qualified professional about your specific situation. TrueMeasureKit is not liable for decisions made based on these results. See our Terms of Service.
Why smokers need more, regardless of other factors
Vitamin C is a water-soluble antioxidant, and smoking increases oxidative stress in the body while also lowering vitamin C levels in the blood — the NIH's own guidance adds a flat 35mg/day for smokers on top of whichever baseline applies, rather than treating it as a separate category. Unlike fat-soluble vitamins, the body can't store large reserves of vitamin C, so the recommended amount reflects a genuine daily need rather than a one-time buffer.
Frequently asked questions
Why is the target higher for smokers?
Smoking increases oxidative stress in the body, and the NIH-published RDA accounts for this by recommending an additional 35mg per day for smokers compared to non-smokers of the same age and sex.