Vitamin D Levels: Normal Range, Testing and What the Blood Test Costs

In Germany, a vitamin D level of 50 nmol/l or more, which is 20 ng/ml, is considered sufficient. Below 30 nmol/l (12 ng/ml) counts as a deficiency, and experts call everything in between suboptimal. The test measures 25-hydroxyvitamin D (25(OH)D), the storage form of vitamin D in your blood. Without a specific suspicion of deficiency, you usually pay for the test yourself. The lab alone costs around €28 to €32, and the blood draw and consultation come on top.

On the lab report, unfortunately, it often looks less clear-cut. Some labs actually flag a value that the German Nutrition Society (DGE) still considers sufficient. So that you can still make sense of your own number, no matter which unit it appears in on your report, you'll find all the cutoffs here in both units. How you would even notice a deficiency in everyday life is covered in our article on vitamin D deficiency.

What is a normal vitamin D level?

A normal 25(OH)D level is between 50 and 125 nmol/l, so 20 to 50 ng/ml. These cutoffs come from a 2011 report by the US Institute of Medicine. According to it, 50 nmol/l covers the needs of at least 97.5% of all people for healthy bones, and from 125 nmol/l on, doctors should start paying attention. Germany's public health institute, the Robert Koch Institute (RKI), divides the range below that the same way in its fact sheet on vitamin D status in Germany. Put together, it looks like this:

Fortunately, the last row is the exception, because according to a clinical review on vitamin D toxicity, experts usually only speak of toxicity at levels above 375 nmol/l, and you practically only get there with very high doses over months.

Converting vitamin D levels: ng/ml to nmol/l

To convert, you only need one number, because one ng/ml equals 2.5 nmol/l. So you multiply the ng/ml value by 2.5, and in the other direction you divide by 2.5. We've worked out the values that show up on lab reports most often:

What does a vitamin D test actually measure?

The vitamin D test measures 25(OH)D, also called calcidiol. Your liver converts all the vitamin D that comes from sun, food or supplements into this storage form. The standard test doesn't measure the active vitamin D hormone your cells ultimately work with, because that reveals surprisingly little about your supply.

With a half-life of around 15 days, the storage form stays in your blood for a long time, the active hormone only about 15 hours. Think of it like a river: the active hormone is the single wave passing by right now, the storage form is the water level. That's why 25(OH)D shows you pretty reliably how well your reserves were filled over the past few weeks.

Why do labs use different normal ranges?

Some labs set the lower limit at 50 nmol/l (20 ng/ml), others already at 75 nmol/l (30 ng/ml). Germany's Federal Institute for Risk Assessment (BfR) points this out too in its questions and answers on vitamin D. The BfR itself goes by the 50 nmol/l and notes that not everyone with levels between 30 and 50 nmol/l is "undersupplied per se". So a level of 60 nmol/l can be completely unremarkable on one report and get an asterisk on another.

Behind this is a long and still open debate about which level would really be optimal beyond bone health. The Endocrine Society, the US professional society of endocrinologists, even dropped a target value altogether in 2024. In its guideline on vitamin D, it writes that there is no clear evidence for the optimal level needed to prevent disease. For bones, on the other hand, the cutoff is well supported. That's why we stick to the 50 nmol/l.

This also fits with what the EU officially attributes to vitamin D. The list of authorized health claims includes these, among others: Vitamin D contributes to the maintenance of normal bones, to the maintenance of normal muscle function, to the normal function of the immune system and to normal absorption/utilisation of calcium and phosphorus. None of these claims names a target level in the blood. And for tiredness, mood or hair, there are none at all. So your lab value shows you how full your stores are. Where persistent tiredness comes from, for example, it can't explain on its own, though. Everything else vitamin D does in your body is written up in detail in our guide to D3 and K2.

When does a vitamin D test make sense?

A vitamin D test makes sense above all if you have symptoms that fit a deficiency, if you belong to a risk group or before you plan to take clearly more vitamin D than usual. For healthy adults without any suspicion, on the other hand, experts tend to advise against routine testing, the Endocrine Society just as much as the DGE, which puts it like this on its FAQ page on vitamin D (our translation): "Since a vitamin D deficiency cannot be assumed for the majority of the healthy German population, vitamin D status should only be determined if there is a well-founded suspicion of deficiency or in people at risk."

The DGE counts older people above all among the risk groups, because with age their skin can make less than half as much vitamin D as it used to, plus people with dark skin and anyone who rarely gets outside, for example because they need care. Some long-term medications can also change your vitamin D balance, for example certain epilepsy drugs or cortisone. And significant excess weight lowers the level as well: with obesity, it was around 20 nmol/l lower in a large Canadian analysis. For pregnancy, breastfeeding and menopause, there's a separate article: vitamin D for women.

For everyone else, that's actually good news, because you can take a moderate amount of vitamin D without a test. The BfR writes that anyone who wants to supplement vitamin D can turn to products with up to 20 µg (800 IU) per daily dose, and that higher doses should only be taken under medical supervision. And the guideline of Germany's bone specialists from the umbrella organization for osteology (DVO), which is aimed at postmenopausal women and men over 50, even considers 800 to 1,000 IU daily without blood checks acceptable.

How much does a vitamin D test cost, and does insurance pay for it?

In Germany, statutory health insurance covers the vitamin D test if a suspected deficiency is medically justified. Without that suspicion, it's an Individual Health Service (IGeL), which you pay for yourself. The IGeL-Monitor, run by the Medical Service of the German health insurers, lists lab costs between €27.98 and €32.18 for it, with the blood draw and medical consultation on top. The German consumer advice center (Verbraucherzentrale) gives prices between €20 and €50 for the measurement at a doctor's office.

The IGeL-Monitor rates the benefit for people without symptoms pretty soberly (our translation): "We rate early detection screening for vitamin D deficiency as 'unclear'." That doesn't mean the test is bad. There just aren't any studies yet showing whether healthy people get anything out of this kind of screening. So if you belong to a risk group or have symptoms, say exactly that at the doctor's office. Then it's a diagnostic workup and no longer screening, and insurance can cover the cost.

There are also home tests, where you send a few drops of blood from your fingertip to the lab yourself. The BfR points out, however, that vitamin D readings often differ depending on method, test and lab, and of course that applies to the test from your mailbox just the same. Our take: for a first impression, a test like this can be enough, but if the result is clearly below 30 or above 125 nmol/l, have it confirmed by your family doctor before you change your vitamin D intake significantly because of it.

When should you test, and when should you retest?

A level tells you the most if you know what time of year it was measured, because vitamin D follows the sun. In the nationwide RKI survey from 2008 to 2011, levels were highest from June to September and dropped noticeably from October on. In winter, the average was 35 nmol/l for women and 31 nmol/l for men, in summer 59 and 62 nmol/l. So the same person can be well supplied in August and running low in February. A summer level tends to show you your peak, a level from late winter rather your low point. And if you want to compare two measurements, ideally take them in the same season.

Neither the DGE nor the Endocrine Society nor the DVO guideline calls for regular checks in healthy people. If you still want to retest after a change, for example because you're taking a higher dose under medical guidance, then in our view no earlier than after about three months, because the storage form only shifts over weeks. In a study from Toronto, whose participants started taking 25 µg (1,000 IU) of vitamin D3 daily in January and February, the level rose clearly and was stable from the third month on. How quickly vitamin D works after you start is covered in more detail under vitamin D: when to take it and how fast it works.

You usually won't feel good vitamin D status directly, but you can certainly measure it. With RISE by Fifty Five, that's no different. Each micro capsule provides 50 µg (2,000 IU) of vitamin D3, plus K2 as MK-7, and the jar says: one every two days with a main meal. We suggest the morning or midday. On average, that gets you to 25 µg (1,000 IU) a day, so the amount the participants in Toronto got daily. Still, you can't simply transfer their increase to yourself, because everyone starts from a different level, and weight and season have a say too. Where you end up is best shown by your own measurement.

Your vitamin D level is too low or too high: what now?

If your level is below 30 nmol/l (12 ng/ml), talk to your doctor about how to bring it back up. At that point, it's about more than basic supply. In our view, higher doses only make sense if a blood test shows a deficiency, and then in consultation with your doctor.

Between 30 and 50 nmol/l, simple steps usually get you further. The DGE calculated its 20 µg (800 IU) a day precisely so that you reach 50 nmol/l with it even without any sun at all. How much is right for you is covered under daily vitamin D needs. And if you'd rather start with sun and food first: what the sun can contribute is explained under sun and vitamin D, and what your food provides in our table of vitamin D foods.

If your level is above 125 nmol/l (50 ng/ml), it's worth first taking a look at all the supplements you take and having a talk at the doctor's office, especially if high-dose weekly or monthly doses are part of the mix. When it really becomes too much and how you would notice, we explain in our article on overdose and side effects.

FAQ

Is a vitamin D level of 20 or 30 ng/ml too low?

A level of 20 ng/ml equals 50 nmol/l and sits exactly at the cutoff from which the DGE, RKI and BfR classify your supply as sufficient. Labs with a lower limit of 30 ng/ml will still flag it, though. At 30 ng/ml, which is 75 nmol/l, you're well supplied by all common cutoffs.

Is vitamin D part of a complete blood count?

No, not even of a complete blood count. A blood count counts your blood cells, whereas 25(OH)D is a separate lab value that your doctor has to order specifically. So an unremarkable checkup doesn't tell you anything about your vitamin D for now.

Does a vitamin D capsule the day before skew the test result?

Hardly, because what's measured is the storage form, and it shifts over weeks. The vitamin D3 from the capsule itself does rise briefly in the blood, but according to the BfR it only has a half-life of about 20 hours, and it's not what the test measures either. In our view, you don't need to pause your intake before the appointment, but do feel free to mention at the doctor's office that you take vitamin D.

Can I take vitamin D without a test?

Yes, you can take a moderate amount just fine without measuring first, and the BfR and the German bone guideline both consider that safe. You mainly need a test if you want to take a clearly higher dose or have a specific suspicion.

Is a vitamin D supplement worth it if my level is low?

A low level is exactly the situation a supplement is meant for. And that's precisely where even a moderate amount shows up pretty clearly in the blood. In older women in a US study, a daily amount of just 20 µg (800 IU) raised the level by around 24 nmol/l within three months, from the suboptimal well into the sufficient range. The women there had dark skin and started out low, so your increase may turn out differently. How far it goes, a check after a few months will then show you.

Disclaimer:

This article is for informational purposes only and does not replace medical advice, diagnosis, or treatment by a physician or pharmacist. The information provided here should not be used for self-diagnosis or self-treatment. Food supplements are no substitute for a balanced, varied diet and a healthy lifestyle. For any health questions or complaints, please always consult a doctor you trust. Fifty Five accepts no liability for any inconvenience or harm resulting from the use of the information presented here.

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