Vitamin D Status Interpreter

Place a 25-hydroxyvitamin D against every framework still in circulation — Endocrine Society 2011, withdrawn by the Endocrine Society in 2024, and the IOM’s genuinely different position — in ng/mL and nmol/L, without pretending one has won.

Last updated 17 Sep 2026

25(OH)D against each framework still in use

Level + population → each framework's view

Unit of the resultBoth are in daily use and the factor between them is 2.496: ng/mL × 2.496 = nmol/L. A 25(OH)D of 20 ng/mL is 49.9 nmol/L and 30 ng/mL is 74.9 nmol/L, which is why the literature quotes 50 and 75 nmol/L as the round-number equivalents. µg/L is numerically identical to ng/mL. The factor comes from the molecular weight of 25-hydroxyvitamin D3, 400.64 daltons; 25-OH-D2 is 412.65, so applying the D3 factor to the D2 fraction introduces an error of about 3% in that fraction only, which is the universal convention rather than a mistake.

Total 25-hydroxyvitamin DTotal 25(OH)D — the D2 and D3 forms combined, which is what a status assay reports and the only form that answers the question. Do not enter a 1,25-dihydroxyvitamin D (calcitriol) result here: it is a different analyte, reported in pmol/L, tightly regulated by PTH, and frequently normal or high in vitamin D deficiency because the deficiency drives the conversion. Enter the number in whichever unit you selected above.

PopulationThe 2024 Endocrine Society guideline’s recommendations are population-based rather than threshold-based: it suggests empiric supplementation — intake above the dietary reference intake, without measuring 25(OH)D at all — for children and adolescents aged 1 to 18, adults aged 75 and over, pregnancy, and adults with high-risk prediabetes, and suggests against routine 25(OH)D screening in every population it considered. So in four of the five options here the guideline’s answer does not depend on the number, which is itself the most useful thing this selector can tell you.

20 to 30 ng/mL (50 to 75 nmol/L) — insufficient to one framework, sufficient to anotherExample

25(OH)D 24 ng/mL in an otherwise healthy adult aged 41

The three frameworks, each labelled with whose it is

The rows are not three versions of one answer. The 2011 Endocrine Society thresholds are the ones almost every online calculator and many laboratory reports still use, and the body that wrote them withdrew them in 2024 — “no longer endorses the target 25(OH)D level of 30 ng/mL (75 nmol/L)”, and “no longer endorses specific 25(OH)D levels to define vitamin D sufficiency, insufficiency, and deficiency”. The IOM’s position was never the same position: 20 ng/mL covers practically everyone for bone health, which is the 2011 Endocrine Society’s deficiency threshold and 10 ng/mL below its target. And the 2024 guideline sets no numbers at all, which is a deliberate choice rather than an omission: it found no clinical trial evidence for thresholds tied to outcome-specific benefits.
Framework	Status	Deficient	Between	Adequate / target	Too high
Endocrine Society 2011 (Holick et al.)	Withdrawn by the Endocrine Society in 2024	Under 20 ng/mL (under 50 nmol/L)	Insufficiency, 21–29 ng/mL (52.5–72.5 nmol/L)	30–100 ng/mL (75–250 nmol/L)	Above 100 ng/mL
IOM / NAM 2011 dietary reference intakes	Current; the intake standard the 2024 guideline defers to	Below 40 nmol/L (16 ng/mL) is below the average requirement	—	At least 50 nmol/L (20 ng/mL): “practically all persons are sufficient”	Above 125 nmol/L (50 ng/mL): “there may be reason for concern”
Endocrine Society 2024	Current	No numeric threshold endorsed	No numeric threshold endorsed	No target endorsed; defers to the IOM’s dietary reference intakes	No numeric threshold endorsed

The same level in both units

The factor is 2.496, derived from the molecular weight of 25-hydroxyvitamin D3 (400.64 daltons): 1 ng/mL is 1×10⁻⁶ g/L, and 1×10⁻⁶ ÷ 400.64 = 2.496×10⁻⁹ mol/L. The round nmol/L figures in the literature — 50, 75, 125 — are 20.03, 30.05 and 50.08 ng/mL rather than exactly 20, 30 and 50, so a value sitting precisely on a threshold can fall on different sides of it in the two units. The site’s vitamin D unit converter handles the arithmetic in either direction, including µg/L.
ng/mL	nmol/L	Where it falls
10	25.0	Deficiency on every framework; rickets and osteomalacia territory
12	30.0	The level commonly quoted as the floor below which bone disease is the question
16	39.9	The IOM’s average requirement (40 nmol/L)
20	49.9	Endocrine Society 2011 deficiency threshold; IOM’s “practically all persons are sufficient”
24	59.9	2011 insufficiency; IOM sufficient; 2024 unclassified
30	74.9	The withdrawn 2011 target (quoted as 75 nmol/L)
40	99.8	Comfortably inside every framework’s adequate range
50	124.8	The IOM’s level of possible concern (quoted as 125 nmol/L)
100	249.6	Top of the withdrawn 2011 sufficiency band

What the 2024 guideline does say

Read this table beside the first one and the shape of the 2024 guideline becomes clear: it replaced a threshold with a population. The doses in the third column are the weighted averages of what the trials it reviewed actually used, not dose recommendations, and the guideline describes empiric supplementation as intake exceeding the dietary reference intakes rather than as a specific regimen. On treating established deficiency the retrievable text of the 2024 guideline is silent, so the regimens most protocols use remain the 2011 ones — 50,000 IU weekly for 8 weeks then 1500 to 2000 IU daily in adults, and 2000 IU daily or 50,000 IU weekly for at least 6 weeks then 600 to 1000 IU daily in children 1 to 18 — attributed to the 2011 guideline and not to the 2024 one. The site’s vitamin D IU to microgram converter converts between the two dose units.
Recommendation	Population	Trial weighted-average dose
Empiric supplementation, without measuring 25(OH)D	Children and adolescents, 1 to 18 years	About 1200 IU/day (30 µg)
Empiric supplementation, without measuring 25(OH)D	Adults 75 years and over	About 900 IU/day (23 µg)
Empiric supplementation, without measuring 25(OH)D	Pregnancy	About 2500 IU/day (63 µg)
Empiric supplementation, without measuring 25(OH)D	Adults with high-risk prediabetes	About 3500 IU/day (88 µg)
Suggests against routine 25(OH)D testing	Every population considered, including healthy adults under 75, adults 75+, pregnancy, people with dark complexion and people with obesity	—
Baseline intake standard	Everyone	The IOM’s dietary reference intakes, which the panel assumed as a baseline for all individuals
Numeric 25(OH)D thresholds	—	None endorsed

The body that set the thresholds withdrew them, and that is the story

Most pages about vitamin D print one table of cut-offs: deficient below 20 ng/mL, insufficient 20 to 30, sufficient above 30. Those numbers come from the Endocrine Society’s 2011 clinical practice guideline, and in 2024 the Endocrine Society withdrew them. Its words are unambiguous: the guideline “no longer endorses the target 25(OH)D level of 30 ng/mL (75 nmol/L) suggested in the previous guideline”, and it “no longer endorses specific 25(OH)D levels to define vitamin D sufficiency, insufficiency, and deficiency”. Its accompanying commentary put the reasoning plainly: the available trial evidence does not clearly show that net benefit from vitamin D in generally healthy people is predicted by 25(OH)D concentrations below about 20 to 24 ng/mL. A reader working from the 2011 table is working from a framework its own author has retired.

What replaced it is not a new table. The 2024 guideline suggests against routine 25(OH)D testing in every population it considered — healthy adults under 75, adults of 75 and over, pregnancy, people with dark complexion, people with obesity — and instead recommends empiric supplementation, meaning intake above the dietary reference intake without measuring a level, for four specific groups: children and adolescents aged 1 to 18, adults aged 75 and over, pregnancy, and adults with high-risk prediabetes. For intake standards it defers to the Institute of Medicine, whose dietary reference intakes the panel assumed as a baseline for everyone. A threshold was replaced by a population.

The Institute of Medicine’s position is the one most often misdescribed as a lower version of the same thing, and it is not. Reviewing the evidence for population requirements, the IOM concluded that “practically all persons are sufficient at serum 25OHD levels of at least 50 nmol/L (20 ng/mL)”, with 40 nmol/L (16 ng/mL) as the average requirement and 125 nmol/L (50 ng/mL) as the level above which there may be reason for concern. That is a different claim about what the evidence supports, arrived at by a different body for a different purpose. The IOM also recorded the consequence of the disagreement: it warned that a considerable over-estimation of vitamin D deficiency in the North American population existed because of the use by some of cut-points that greatly exceed the levels its own report identified.

So the practical picture is this. Below about 10 ng/mL (25 nmol/L) everyone agrees, and that is where rickets and osteomalacia live; a result there deserves treatment and a search for a cause, not a discussion about frameworks. Between 20 and 30 ng/mL is where the whole argument sits: insufficiency to a withdrawn framework, sufficiency to a current one, unclassified by the body that wrote the first. Between 30 and 50 ng/mL everyone is content. Above 50 ng/mL the frameworks conflict again, less visibly — inside the withdrawn 2011 sufficiency band and above the IOM’s level of possible concern at the same time.

Which is why this page shows a value against each framework and labels each one with whose it is and whether it still stands, rather than returning a single word. Picking a winner would be inventing a consensus that does not exist, and the reader who came here with a 24 ng/mL result is better served by knowing that two reputable bodies would classify it differently than by being told it is ‘insufficient’. For the arithmetic rather than the interpretation, the vitamin D unit converter handles ng/mL, nmol/L and µg/L, and the vitamin D IU to microgram converter handles doses. If the question behind the test was bone rather than vitamin status, the albumin-corrected calcium, the PTH converter and the BMD T-score and Z-score calculator are where the answers are.

Frequently asked questions

Did the Endocrine Society withdraw its vitamin D thresholds?

Yes. The 2024 guideline states that it “no longer endorses the target 25(OH)D level of 30 ng/mL (75 nmol/L) suggested in the previous guideline” and that it “no longer endorses specific 25(OH)D levels to define vitamin D sufficiency, insufficiency, and deficiency”. Its accompanying commentary explains that the trial evidence does not clearly show net benefit in generally healthy people predicted by levels below about 20 to 24 ng/mL. No numeric replacement was issued.

What counts as vitamin D deficiency now?

There is no single current answer, which is the honest position. The 2011 Endocrine Society threshold of under 20 ng/mL (50 nmol/L) has been withdrawn by its own author. The IOM holds that practically all persons are sufficient at 50 nmol/L (20 ng/mL) or above, with 40 nmol/L (16 ng/mL) as the average requirement. Below about 25 to 30 nmol/L (10 to 12 ng/mL) every framework agrees the level is deficient and associated with rickets and osteomalacia, and that part of the range is not disputed.

Is 25 ng/mL sufficient or insufficient?

It depends whose framework you use, and that is the finding rather than an evasion. 25 ng/mL is 62.4 nmol/L. The 2011 Endocrine Society guideline called 21 to 29 ng/mL insufficiency; the IOM says practically all persons are sufficient at 20 ng/mL or above, so on its reading 25 is adequate; and the 2024 Endocrine Society guideline endorses no threshold either way. Nothing in force calls it deficient, one withdrawn framework called it insufficient.

Should vitamin D be tested routinely?

The 2024 Endocrine Society guideline suggests against routine 25(OH)D testing in every population it considered, including healthy adults under 75, adults aged 75 and over, pregnancy, people with dark complexion and people with obesity. Its reasoning includes that an appropriate actionable 25(OH)D level remains unknown. The 2011 guideline had already recommended against population screening in people not at risk, while supporting testing in those at risk. Testing to investigate suspected osteomalacia, malabsorption, unexplained hypocalcaemia or metabolic bone disease is a different question and is not what either recommendation addresses.

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

Multiply by 2.496. The factor comes from the molecular weight of 25-hydroxyvitamin D3, 400.64 daltons: 1 ng/mL is 1×10⁻⁶ g/L, and dividing by 400.64 gives 2.496 nmol/L. So 20 ng/mL is 49.9 nmol/L, 30 is 74.9 and 50 is 124.8 — which is why the literature rounds them to 50, 75 and 125 nmol/L. µg/L is numerically identical to ng/mL.

What does the 2024 guideline recommend instead of thresholds?

Empiric supplementation for specific populations, without measuring a level: children and adolescents aged 1 to 18, adults aged 75 and over, pregnancy, and adults with high-risk prediabetes. The trials it reviewed used weighted average doses of roughly 1200, 900, 2500 and 3500 IU a day respectively. For baseline intake it defers to the IOM’s dietary reference intakes. On treating established deficiency the guideline’s retrievable text is silent, so the widely used regimens remain the 2011 ones.

Can a vitamin D level be too high?

Yes. The IOM states that there may be reason for concern above 125 nmol/L (50 ng/mL), which is a statement about absent additional benefit and some signal of harm rather than a diagnosis of toxicity. Frank toxicity with hypercalcaemia occurs well above that and comes from supplements, never from sunlight. If a level is unexpectedly high, total up the intake from all products and check for a microgram-versus-international-unit error, which is a tenfold mistake, then check an albumin-adjusted calcium, PTH and renal function.

Related calculators

References

Demay MB, Pittas AG, Bikle DD, et al. Vitamin D for the prevention of disease: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2024 — the withdrawal of the 30 ng/mL target and of the specific levels defining sufficiency, insufficiency and deficiency; the recommendation against routine 25(OH)D testing; the four empiric-supplementation populations with their trial weighted-average doses; and the deferral to the IOM’s dietary reference intakes.
Demay MB, et al. Vitamin D insufficiency and epistemic humility: an Endocrine Society guideline communication. J Clin Endocrinol Metab. 2024;109(8):1948 — the Society’s own account of why it no longer endorses its previous definitions of sufficiency and insufficiency.
Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96(7):1911–1930 — the withdrawn thresholds (deficiency below 20 ng/mL, insufficiency 21–29, sufficiency 30–100), the target above 30 ng/mL, the risk-based screening position and the treatment regimens.
Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D. Washington DC: National Academies Press; 2011 (Summary, NBK56050) — 40 nmol/L (16 ng/mL) as the average requirement, “practically all persons are sufficient at serum 25OHD levels of at least 50 nmol/L (20 ng/mL)”, concern above 125 nmol/L (50 ng/mL), and the warning about over-estimation of deficiency from inflated cut-points.
The 2024 Endocrine Society guideline on vitamin D: comprehensive summary and critical appraisal. Nutrients. 2026;18(9):1472 — an independent appraisal confirming the withdrawal of the 2011 thresholds, the 2011 values themselves in both units, and the guideline’s endorsement of the IOM framework.

Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.