UL is the Tolerable Upper Intake Level — the highest daily intake unlikely to pose risk for almost all individuals. Not all vitamins have a UL.

Do I need supplements if I meet the RDA from food?

Generally no, if your intake is consistent and you have no special conditions. Supplements can help fill gaps but may pose risks at high doses.

Why does the calculator use RDAs/AIs by age and sex?

Requirements vary with age, sex, and life stage due to physiology, metabolism, and reproductive status.

Can this calculator diagnose deficiencies?

No. It is an educational tool. Clinical assessment and lab tests are needed to diagnose deficiencies or toxicities.

How accurate are my intake estimates?

Food labels and reputable databases help, but day-to-day variability is high. Consider averaging over multiple days and consulting a dietitian.

What about bioavailability and interactions?

Absorption can vary by form and co-ingestion (e.g., fat improves vitamin D and A absorption). The tool compares totals to reference values; it does not model bioavailability.

Vitamin Calculator — Personalized RDAs, AIs & ULs by Age & Sex

Enter your age, sex, and (if applicable) pregnancy/lactation status, then add daily vitamin intakes. The tool compares them against life-stage specific RDAs/AIs and checks Upper Intake Levels (UL). Designed for dietitians, clinicians, and informed consumers who need a fast, transparent check.

Authoritative data source & methodology

Primary reference: Dietary Reference Intakes (DRIs) by the National Academies (Institute of Medicine/Health and Medicine Division) and NIH Office of Dietary Supplements (ODS) fact sheets. Selected life-stage values align to RDA or AI where applicable; ULs are included when defined.
Key portals: NIH ODS—Nutrient Recommendations, USDA DRI Calculator, Australian NRVs portal.

Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.

The formula explained

\[ \text{Percent of Requirement}~(\%) = \frac{\text{Your Intake}}{\text{RDA or AI for your life stage}} \times 100 \] \[ \text{UL Check}:~~ \text{Flag High if}~~ \text{Your Intake} > \text{UL (if defined)} \]

Glossary of variables

Your Intake: Estimated daily amount you consume from food + supplements.
RDA (Recommended Dietary Allowance): Average daily level sufficient for ~97–98% of healthy individuals.
AI (Adequate Intake): Used when evidence is insufficient for an RDA.
UL (Upper Intake Level): Highest daily intake unlikely to pose risk.
% of RDA/AI: Intake as a percentage of your life-stage reference value.

How it works: a step-by-step example

Example day (Male, 30 years, General)

Suppose your estimated intakes are: Vitamin C = 60 mg, Vitamin D = 15 µg, Folate = 320 µg DFE, Vitamin B12 = 2.4 µg.

If the RDA/AI values are: C = 90 mg, D = 15 µg, Folate = 400 µg DFE, B12 = 2.4 µg, then:

\[ \%C = \frac{60}{90}\times 100 \approx 67\% \quad (Low) \\ \%D = \frac{15}{15}\times 100 = 100\% \quad (OK) \\ \%\text{Folate} = \frac{320}{400}\times 100 = 80\% \quad (Low) \\ \%\text{B12} = \frac{2.4}{2.4}\times 100 = 100\% \quad (OK) \]

The tool will flag Vitamin C and Folate as Low. If any intake exceeds a defined UL, it is flagged High.

Frequently asked questions

Are RDAs and AIs the same?

No. RDAs have stronger evidence; AIs are set when data are insufficient. The tool displays whichever applies.

What is a UL and why does it matter?

It’s a safety cap. Regularly exceeding a UL may increase adverse effect risks, especially with supplements.

Can I switch units?

Units follow DRI conventions (e.g., vitamin A in µg RAE, folate in µg DFE). This avoids conversion ambiguity.

Does sunlight change vitamin D requirements?

DRIs assume minimal sun exposure. Individual synthesis varies; consult local guidance and clinicians.

Will this diagnose deficiency or toxicity?

No. It’s an educational estimator. For medical advice, see a qualified professional.

Tool developed by Ugo Candido. Content verified by CalcDomain Editorial Board.
Last accuracy review: October 29, 2025

vitamin calculator

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Results overview

Vitamins below RDA/AI

Vitamins above UL

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