Most adults need 600 IU (15 micrograms) of vitamin D per day. Adults over 70 need 800 IU (20 micrograms), and infants need 400 IU (10 micrograms). The safe upper limit for adults is 4,000 IU a day from all sources combined.
These amounts come from the National Academies and are published by the NIH Office of Dietary Supplements. They remain the official US guidance as of October 2026. Below are the numbers by age, how much you can get from food and sun, and when people may need more.
Recommended vitamin D per day by age
The table shows the daily recommended amount and the upper limit for each group. The upper limit is the most you can take daily without a likely risk of harm. It is not a target.
| Age or group | Recommended per day | Upper limit per day |
|---|---|---|
| Birth to 6 months | 10 mcg (400 IU) | 25 mcg (1,000 IU) |
| 7 to 12 months | 10 mcg (400 IU) | 38 mcg (1,500 IU) |
| 1 to 3 years | 15 mcg (600 IU) | 63 mcg (2,500 IU) |
| 4 to 8 years | 15 mcg (600 IU) | 75 mcg (3,000 IU) |
| 9 to 18 years | 15 mcg (600 IU) | 100 mcg (4,000 IU) |
| 19 to 70 years | 15 mcg (600 IU) | 100 mcg (4,000 IU) |
| 71 years and older | 20 mcg (800 IU) | 100 mcg (4,000 IU) |
| Pregnant or breastfeeding | 15 mcg (600 IU) | 100 mcg (4,000 IU) |
Babies are a special case. Breast milk contains little vitamin D, so pediatricians usually advise a daily 400 IU supplement for breastfed infants, starting soon after birth. Infant formula sold in the US is fortified, which means formula-fed babies often get enough once they drink about a quart a day.
The infant figure is technically an “adequate intake” rather than a full recommended allowance. In practice, though, it is used the same way.
Reading labels: micrograms and IU
Labels may list vitamin D in micrograms (mcg), international units (IU), or both. The conversion is simple: 1 microgram equals 40 IU. So a 25-microgram capsule holds 1,000 IU, and a 50-microgram capsule holds 2,000 IU.
The percent Daily Value on a US label is based on 20 micrograms, or 800 IU. That is why a product with 600 IU may show 75% even though 600 IU fully covers most adults.
Supplements come in two forms, D2 and D3. Both raise blood levels, but D3 tends to raise them more and keep them up longer. Our guide to vitamin D vs. D3 explains the difference in detail.
How much vitamin D you can get from food
Few foods contain much vitamin D naturally. Fatty fish leads the list, while most Americans get the rest from fortified foods. These figures come from the NIH health professional fact sheet.
| Food and serving | Vitamin D |
|---|---|
| Cod liver oil, 1 tablespoon | 1,360 IU |
| Rainbow trout, farmed, cooked, 3 ounces | 645 IU |
| Sockeye salmon, cooked, 3 ounces | 570 IU |
| White mushrooms exposed to UV light, 1/2 cup | 366 IU |
| Fortified 2% milk, 1 cup | 120 IU |
| Fortified soy, almond or oat milk, 1 cup | 100-144 IU |
| Fortified breakfast cereal, 1 serving | 80 IU |
| Egg, 1 large | 44 IU |
| Light tuna, canned in water, 3 ounces | 40 IU |
For example, a serving of salmon nearly covers an adult’s daily need on its own. On the other hand, two glasses of milk and a bowl of cereal supply only about 320 IU. That gap is why many people who rarely eat fish fall short through diet alone.
What sunlight adds
Your skin makes vitamin D when ultraviolet B rays from the sun reach it. How much it makes depends on the season, time of day, latitude, cloud cover, skin color, age and sunscreen use. Because of all these factors, official sources do not set a safe number of minutes in the sun.
In southern California, midday sun carries UVB for much of the year. In northern states, however, winter sunlight is often too weak for the skin to make much vitamin D. People with darker skin also make less from the same exposure, and older skin makes less too.
Sun exposure also raises skin cancer risk. So most doctors suggest getting vitamin D from food or supplements rather than from extra time in the sun.
Who may need more vitamin D
Some groups are more likely to run low, according to the NIH. They include breastfed infants, older adults, and people who get little sun. People with darker skin, obesity, or conditions that limit fat absorption, such as Crohn’s or celiac disease, are on the list too. So are people who have had gastric bypass surgery.
In 2024, the Endocrine Society updated its guideline on vitamin D for disease prevention. It suggests vitamin D above the standard amount for four groups: children and teens aged 1 to 18, pregnant people, adults with high-risk prediabetes, and adults 75 and older. For healthy adults under 75, it advises sticking with the standard amounts. It also recommends against routine blood tests for people without a specific medical reason.
When a doctor does order a test, the NIH uses these general cutoffs for 25-hydroxyvitamin D:
- Below 30 nmol/L (12 ng/mL): too low, which can weaken bones.
- 50 nmol/L (20 ng/mL) or higher: adequate for most people.
- Above 125 nmol/L (50 ng/mL): too high and possibly harmful.
The same guideline also addresses how to take it. For adults over 50 who need extra vitamin D, it suggests a daily dose rather than large doses given weekly or monthly.
If you are deficient, a doctor may prescribe a higher dose for a set period. That is a treatment plan, not a daily habit to copy.
Can you take too much vitamin D?
Yes, though it almost always happens through supplements, not food or sun. According to MedlinePlus, toxicity symptoms usually appear only with doses above 10,000 IU a day. Too much vitamin D raises blood calcium. That can cause nausea, vomiting, weakness, confusion, heavy thirst and kidney stones.
Vitamin D can also interact with some medicines. These include steroids, the weight-loss drug orlistat, some cholesterol drugs and thiazide water pills. If you take any of them, check with your doctor or pharmacist before adding a supplement.
Big claims for high doses have not held up well either. In the large VITAL trial, more than 25,000 US adults took 2,000 IU daily or a placebo for about five years. The vitamin did not lower rates of invasive cancer or major heart events. Large studies like this take years to settle a question, as an older archive report on a multi-year federal health study showed.
This article is general information. Check with your doctor about the right amount for your case. More health explainers are in our health and sports guides.
Frequently asked questions
Is 1,000 IU of vitamin D per day too much?
No, not for healthy adults. It is above the 600 IU recommendation but well below the 4,000 IU upper limit.
Is 5,000 IU of vitamin D a day safe?
It is above the adult upper limit of 4,000 IU. Take that amount only if a doctor prescribes it, usually for a short time to treat a deficiency.
When is the best time to take vitamin D?
Vitamin D is fat-soluble, so many people take it with a meal that contains some fat. The time of day matters less than taking it consistently.
Do I need a vitamin D blood test?
Healthy people usually do not, according to the 2024 Endocrine Society guideline. A doctor may order one if you have symptoms or a condition that raises your risk.
Have a question about this topic? Ask in the comments below. Our editors read every comment and answer questions here, and we add useful answers to the guide.
Sources
- ods.od.nih.gov/factsheets/VitaminD-Consumer
- ods.od.nih.gov/factsheets/VitaminD-HealthProfessional
- endocrine.org/clinical-practice-guidelines/vitamin-d-for-prevention-of…
- academic.oup.com/jcem/article-abstract/109/8/1907/7685305
- medlineplus.gov/ency/article/001594.htm
- nejm.org/doi/full/10.1056/NEJMoa1809944