Normal Vitamin D Levels Chart: nmol/L and ng/mL Explained

Normal vitamin D levels, measured by a 25-hydroxyvitamin D [25(OH)D] blood test, are generally 50 nmol/L (20 ng/mL) or higher for bone and overall health, according to the U.S. National Institutes of Health. Levels below 30 nmol/L (12 ng/mL) suggest deficiency, and levels above 125 nmol/L (50 ng/mL) may be too high.

Key takeaways

• Canadian labs report vitamin D in nmol/L; most U.S. labs use ng/mL. To convert, multiply ng/mL by 2.5 (or divide nmol/L by 2.5).
• The NIH and BC's provincial guideline both treat 50 nmol/L (20 ng/mL) as adequate for bone health in nearly everyone.
• Some labs and older guidelines use a higher target of 75 nmol/L (30 ng/mL), which is why "normal" can look different from one report to the next.
• Routine vitamin D testing is not recommended for healthy adults; testing is usually for people at higher risk or with symptoms.
• Levels in Canada tend to drop in winter, so the time of year you are tested matters.

What is a normal vitamin D level? (chart)

Your doctor measures vitamin D with a 25(OH)D test, which reflects vitamin D from food, supplements and sunlight. The table below uses the ranges from the NIH Office of Dietary Supplements, which match the cut-offs in British Columbia's vitamin D testing guideline.

These ranges are for generally healthy people. If you have kidney disease, a malabsorption condition such as celiac or Crohn's disease, or osteoporosis, your doctor may aim for a different target.

How do you convert vitamin D nmol/L to ng/mL?

If you have a Canadian result and are reading U.S. advice (or the other way around), the conversion is simple: 1 ng/mL = 2.5 nmol/L. Divide a nmol/L result by 2.5 to get ng/mL, or multiply a ng/mL result by 2.5 to get nmol/L.

• 30 nmol/L = 12 ng/mL
• 50 nmol/L = 20 ng/mL
• 75 nmol/L = 30 ng/mL
• 100 nmol/L = 40 ng/mL
• 125 nmol/L = 50 ng/mL

Getting the units wrong is a common reason people panic over a "low" number. A result of 60 is adequate if it is in nmol/L, but it would be on the high side if it were in ng/mL.

Why do labs disagree on a good vitamin D level?

You may see one lab flag anything under 30 ng/mL (75 nmol/L) as "insufficient," while the NIH calls 20 ng/mL (50 nmol/L) adequate. Both numbers come from respected groups. The Institute of Medicine (now the National Academy of Medicine) set 20 ng/mL as enough for bone health in nearly everyone, while the Endocrine Society's 2011 guideline used 30 ng/mL as its target.

In 2024, the Endocrine Society updated its guideline and dropped the 30 ng/mL target, saying the evidence does not support specific cut-offs for sufficiency. Some labs, such as Cleveland Clinic Laboratories, still list 31 to 80 ng/mL as their reference range. The practical takeaway: read your number against the range printed on your own report, and ask your doctor which target makes sense for you.

Lab methods also vary. The NIH notes that different 25(OH)D tests can read falsely high or low, so it helps to use the same lab if you are comparing results over time.

If your doctor suggests a supplement, CLE Vitamin D3 5,000 IU daily capsules are one option: one small capsule a day with a meal helps maintain immune function and healthy bones and teeth. Because 5,000 IU is a higher-strength dose, it is best chosen with your healthcare provider, ideally based on a blood test like the one described here. Right now you can buy 2 bottles and get 1 free.

What vitamin D level is too high?

The NIH links levels above 125 nmol/L (50 ng/mL) with possible adverse effects, and BC's guideline says levels above 375 nmol/L carry a significant risk of toxicity. Very high vitamin D raises blood calcium (hypercalcemia), which can cause nausea, vomiting, muscle weakness, confusion, excessive thirst and kidney stones.

Vitamin D toxicity almost always comes from taking high-dose supplements for a long time, not from sunlight or food. The tolerable upper intake level for adults is 4,000 IU (100 mcg) a day unless a doctor advises otherwise. Our guide to how much vitamin D is too much covers the safe limits and warning signs in more detail.

What causes low vitamin D levels?

Low results usually come from not getting enough vitamin D from sunlight, food or supplements, or from the body not absorbing or processing it well. Common factors include:

• Season and latitude: Canadian research from the University of Toronto Mississauga found levels drop significantly in winter.
• Skin pigmentation: darker skin makes less vitamin D from the same amount of sun.
• Age: older adults make less vitamin D in their skin.
• Limited sun exposure: working indoors, covering skin or always using sunscreen.
• Medical conditions: celiac disease, Crohn's disease, liver or kidney disease and some weight-loss surgeries.
• Certain medications: including some anti-seizure drugs such as phenytoin.
• Higher body weight: vitamin D is stored in body fat, which can lower blood levels.

For symptoms and risk groups, see vitamin D deficiency: signs, who's at risk and how much you need.

Who should get a vitamin D blood test?

Routine screening is not recommended for healthy adults. The Endocrine Society's 2024 guideline advises against routine 25(OH)D testing in the general population, and BC's vitamin D testing guideline also says screening is not needed before or after routine supplementation.

Testing may make sense if you have:

1. A condition that affects absorption, such as celiac or inflammatory bowel disease
2. Kidney or liver disease
3. Osteoporosis, low bone density or a fragility fracture
4. Unexplained bone pain or muscle weakness
5. A medication known to affect vitamin D
6. Possible vitamin D toxicity from high-dose supplements

In BC, MSP covers the test when the patient is under 19 or when a specialist orders it, according to the provincial guideline. Coverage differs in other provinces and U.S. states, so check before booking.

How often should you check your vitamin D level?

If you are tested and start a supplement, many doctors recheck after about three months. A review in American Family Physician notes that levels should be rechecked after three months to confirm the response, because 25(OH)D takes time to level off. After that, there is usually no need for repeat tests unless you have a condition your doctor is monitoring.

Try to compare results from the same season. A summer result can look much better than a February result even if nothing else changed. For tips on dose and timing, read how to take vitamin D: D3 vs D2, best time and how much.

Frequently asked questions

Is 30 nmol/L of vitamin D low?

Yes. A level of 30 nmol/L (12 ng/mL) is at the line the NIH uses for deficiency. Talk to your doctor about the cause and whether a supplement is right for you.

Is 75 nmol/L a good vitamin D level?

Yes. 75 nmol/L (30 ng/mL) is above the 50 nmol/L level the NIH considers adequate for nearly everyone, and it meets the higher target some labs still use.

What is a normal vitamin D level in ng/mL?

The NIH considers 20 ng/mL or higher adequate for bone and overall health, and suggests staying below about 50 ng/mL. Some labs list 30 ng/mL as the lower end of their normal range.

Can you raise your vitamin D level with food alone?

It is hard. Few foods are naturally rich in vitamin D; the main sources are fatty fish such as salmon and trout, egg yolks and fortified milk and plant drinks. Most people get the rest from sunlight or a supplement.

When is the best time of year to test vitamin D?

There is no single best month, but levels in Canada are usually lowest in late winter. If you are retesting, compare results taken at the same time of year.

The bottom line on normal vitamin D levels

Normal vitamin D levels are generally 50 to 125 nmol/L (20 to 50 ng/mL). Check which unit your report uses, compare your number to the range on that report, and talk to your doctor before choosing a dose, especially a higher-strength one. Keep taking any medication you have been prescribed, and do not change it without medical advice.

Sources

• NIH Office of Dietary Supplements: Vitamin D Fact Sheet for Health Professionals
• BC Guidelines: Vitamin D Testing Protocol
• University of Minnesota College of Pharmacy: Comparing the 2011 and 2024 Vitamin D Guidelines
• American Family Physician: Vitamin D Deficiency in Adults

This article is general information, not medical advice. Talk to your doctor or pharmacist before taking vitamin D supplements, especially if you have kidney disease, high calcium levels or take medication.