Sources

Every number in the calculator comes from the official documents below. Values were checked against these sources in September 2026.

US Dietary Reference Intakes (adults)

US DRI adult values
Nutrient	Women	Men	Pregnancy	Lactation	Vegetarian adjustment used	Source
Protein	0.8 g/kg	0.8 g/kg	1.1 g/kg (2nd half)	1.3 g/kg	1.2 g/kg from 70 (NNR planning target)	IOM 2005
Vitamin B12	2.4 µg	2.4 µg	2.6 µg	2.8 µg	—	ODS B12
Iron	18 mg (19–50), 8 mg (51+)	8 mg	27 mg	9 mg	× 1.8	ODS Iron
Zinc	8 mg	11 mg	11 mg	12 mg	× 1.5	ODS Zinc; IOM 2001
Calcium	1,000 mg (19–50), 1,200 mg (51+)	1,000 mg (19–70), 1,200 mg (>70)	1,000 mg	1,000 mg	—	ODS Calcium
Vitamin D	15 µg (19–70), 20 µg (>70)	15 µg (19–70), 20 µg (>70)	15 µg	15 µg	—	ODS Vitamin D
Iodine	150 µg	150 µg	220 µg	290 µg	UL 1,100 µg	ODS Iodine
Omega-3 (ALA, AI)	1.1 g	1.6 g	1.4 g	1.3 g	No RDA for EPA/DHA	ODS Omega-3
Selenium	55 µg	55 µg	60 µg	70 µg	UL 400 µg	ODS Selenium

Nordic Nutrition Recommendations 2023 (adults)

NNR 2023 adult values
Nutrient	Women	Men	Pregnancy	Lactation	Note	NNR table
Protein (RI)	0.83 g/kg	0.83 g/kg	+1 / +9 / +28 g by trimester	+19 g (0–6 mo), +13 g (>6 mo)	≈1.2 g/kg planning target for older adults	Table 11 + text
Vitamin B12 (AI)	4 µg	4 µg	4.5 µg	5.5 µg	—	Table 13
Iron (RI)	15 mg (18–50), 8 mg (51–70; 15 if still menstruating), 7 mg (>70)	9 mg	24 / 25 / 26 mg	15 mg	Assumes mixed diet	Table 14
Zinc (RI)	9.7 / 9.5 / 9.3 mg (18–50 / 51–70 / >70)	12.7 / 12.4 / 12.1 mg	9.7 / 12.1 / 12.1 mg	12.6 mg	Assumes ~600 mg phytate/day	Table 14
Calcium (RI)	1,000 mg (18–24), 950 mg (25+)	1,000 mg (18–24), 950 mg (25+)	950 mg	950 mg	—	Table 14
Vitamin D (RI)	10 µg; 20 µg from 75	10 µg; 20 µg from 75	10 µg	10 µg	20 µg with little or no sun	Table 12
Iodine (AI)	150 µg	150 µg	175 / 200 / 200 µg	200 µg	UL 600 µg	Tables 15, 21
Omega-3	ALA ≥0.5 E%	ALA ≥0.5 E%	ALA ≥0.5 E%	ALA ≥0.5 E%	Total n-3 ≥1 E%	Fat chapter
Selenium (AI)	75 µg	90 µg (85 µg >70)	80 / 85 / 90 µg	85 µg	UL 255 µg	Tables 15, 21

Where NNR gives values per trimester they are listed as 1st / 2nd / 3rd. UL = tolerable upper intake level.

Blomhoff R, Andersen R, Arnesen EK, et al. Nordic Nutrition Recommendations 2023. Copenhagen: Nordic Council of Ministers; 2023. doi:10.6027/nord2023-003. pub.norden.org/nord2023-003
NNR 2023 recommendation tables (Tables 8, 11–15, 21): pub.norden.org/nord2023-003/recommendations.html
NNR 2023 chapters: Vitamin B12, Iron, Zinc, Fat and fatty acids, Selenium

IOM. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press; 2005. nap.nationalacademies.org/catalog/10490
IOM. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. National Academies Press; 2001. nap.nationalacademies.org/catalog/10026 — zinc: “as much as 50 percent greater for vegetarians”.
IOM. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. National Academies Press; 1998. nap.nationalacademies.org/catalog/6015
IOM. Dietary Reference Intakes for Calcium and Vitamin D. National Academies Press; 2011. nap.nationalacademies.org/catalog/13050
IOM. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. National Academies Press; 2000. nap.nationalacademies.org/catalog/9810

Academy of Nutrition and Dietetics. Vegetarian Dietary Patterns for Adults: A Position Paper of the Academy of Nutrition and Dietetics. J Acad Nutr Diet. 2025. PubMed 39923894

See the method page for how these values are combined.