ROOTFUL tool
Vitamin D calculator: what your 25(OH)D result means
Enter the number from your lab report, in ng/ml or nmol/l. You see it converted into the other unit, how a typical Romanian lab classifies it and where it sits against the EFSA target. See the full table.
This tool translates a number; it does not diagnose. The meaning of a result for you depends on your history and context, which only your doctor can assess.
How to read your result in three steps
- Check the unit. Romanian lab reports usually use ng/ml. European guidelines and many international articles use nmol/l. The same value looks 2.5 times bigger in nmol/l, so 24 ng/ml and 60 nmol/l are exactly the same result.
- Look at the range printed on your report. Most Romanian labs use 30 to 100 ng/ml as the reference range, but not all of them. For your result, the range on your own report is the one that counts.
- Compare it with the European target. EFSA considers 50 nmol/l, which is 20 ng/ml, a suitable target for the whole population. Between 20 and 30 ng/ml, the lab and EFSA say different things about the same number.
Why two sources tell you different things
The 30 ng/ml threshold comes from an older position of a professional society, adopted by many labs because it was the most cautious option. In 2024, the same society said the evidence does not allow an adequacy threshold to be set. EFSA, the authority that sets intakes in the European Union, uses 20 ng/ml.
That is why a result of 25 ng/ml can show up in red on your report and still be above the European target. It is not a calculation error, it is two different conventions. We explain each threshold in detail in our guide to normal vitamin D levels.
The month of your test matters
At Romania's latitude, the skin makes far less vitamin D from October to March. Values are usually lowest at the end of winter and highest at the end of summer. A test in February and one in August, for the same person, can look very different. If you want to compare two results, take them at the same time of year and, if possible, at the same lab.
What this calculator does not do
The calculator translates a number into the two languages in circulation, the lab's and EFSA's. It does not diagnose, it does not recommend a dose and it does not take into account your medical history, pregnancy, kidney conditions or the treatments you are on. High doses and loading schemes are for your doctor to decide.
If you are wondering how much to take or when, read how many units of vitamin D a day and when to take vitamin D.
25(OH)D values: ng/ml, nmol/l and what each threshold says
1 ng/ml equals 2.5 nmol/l. Romanian labs usually treat 30 to 100 ng/ml as the reference range, while EFSA sets 50 nmol/l, which is 20 ng/ml, as the target for the whole population.
| ng/ml | nmol/l | Typical lab report | EFSA target (50 nmol/l) |
|---|---|---|---|
| under 10 | under 25 | Severe deficiency | Below |
| 10 to 19 | 25 to 49 | Deficiency | Below |
| 20 to 29 | 50 to 74 | Relative insufficiency | Met |
| 30 to 100 | 75 to 250 | Within the reference range | Met |
| over 100 | over 250 | Above the lab range | No added benefit |
Quick conversions: 12 ng/ml = 30 nmol/l · 20 ng/ml = 50 nmol/l · 30 ng/ml = 75 nmol/l · 40 ng/ml = 100 nmol/l. The Romanian adult guideline considers over 20 ng/ml sufficient, and the 2024 professional society guideline set no threshold at all. Bands can differ slightly from lab to lab; the range printed on your own report is the one that applies to it.
From the ROOTFUL range
Our D3 gummies contain 4000 IU per two gummies, which is the EFSA upper limit for adults, not a maintenance dose for everyone. Without a documented low value or a doctor's advice, a modest intake is enough.
Frequently asked questions
What are normal vitamin D levels in ng/ml?
Romanian labs usually print a reference range of 30 to 100 ng/ml. EFSA sets 20 ng/ml, which is 50 nmol/l, as the target, and the Romanian adult guideline considers anything over 20 ng/ml sufficient.
How do I convert nmol/l to ng/ml?
Divide by 2.5. For example, 50 nmol/l is 20 ng/ml and 75 nmol/l is 30 ng/ml. To convert the other way, multiply ng/ml by 2.5.
What does 25(OH)D mean on a lab report?
25(OH)D, or 25 hydroxyvitamin D, is the storage form of vitamin D in the blood. It is the standard test for vitamin D status because it changes slowly, over weeks and months, not from one day to the next.
My vitamin D is 25 ng/ml. Is that serious?
It does not mean you have a disease. The value is below the range printed by many labs but above the EFSA target of 20 ng/ml. What it means for you, given your history and context, is for your doctor to say.
When should I retest my vitamin D?
After 3 to 4 months at the earliest, because the value changes slowly. To compare fairly, test at the same time of year and, if possible, at the same lab.
Can vitamin D be too high?
Yes. Values above the lab range bring no extra benefit, and very high values usually come from high doses taken for a long time. EFSA has set a tolerable upper intake level of 100 µg a day for adults, which is 4000 IU, from all sources combined.
