Testosterone Units Converter
Convert testosterone levels between ng/dL and nmol/L instantly. Enter your lab result, pick the unit, and see the equivalent value compared with typical male and female reference ranges.
Convert Testosterone Between ng/dL and nmol/L
Testosterone Units Formula
Where:
- \(28.842\) — conversion factor derived from the molecular weight of testosterone, 288.42 g/mol
- \(\text{ng/dL}\) — nanograms per decilitre, the unit used by most US laboratories
- \(\text{nmol/L}\) — nanomoles per litre, the SI unit used in most of Europe, Canada and Australia
The factor 28.842 comes from unit analysis: 1 nmol of testosterone weighs 288.42 ng, and a litre contains 10 decilitres, so 1 nmol/L equals 28.842 ng/dL. The same logic is used in our cholesterol units converter and blood sugar converter, though each substance has its own molecular weight.
Testosterone Units – Calculation Example
Example: a lab report from a US laboratory shows a total testosterone of 500 ng/dL for an adult man, and you want the value in SI units.
\[ \text{nmol/L} = \frac{500}{28.842} = 17.34 \]
Result: 500 ng/dL = 17.34 nmol/L, which falls within the typical adult male reference range (about 300–1000 ng/dL, or 10.4–34.7 nmol/L).
How to Use the Calculator
- Enter your lab result in the Testosterone value field.
- Select ng/dL or nmol/L from the Unit dropdown to match the unit printed on your report.
- Choose Male or Female under Sex (for context). This is used only to compare your result with typical reference ranges.
- Read both converted values — ng/dL and nmol/L — plus a short interpretation in the What this means section.
What the Testosterone Units Mean
Testosterone in blood is reported either in mass concentration (ng/dL, common in the United States) or in molar concentration (nmol/L, the SI standard elsewhere). Because the two systems measure the same molecules differently, comparing results from labs in different countries — or reading international research papers — requires conversion. A healthy adult male range of roughly 300–1000 ng/dL, for instance, corresponds to about 10.4–34.7 nmol/L.
The conversion is exact and depends only on the molecular weight of testosterone (288.42 g/mol). It works the same way for total testosterone, free testosterone calculated from total, or any other testosterone measurement, as long as both values use the same basis. It does not convert between total and free testosterone — those are different measurements that require a separate calculation involving SHBG and albumin.
The interpretation shown alongside the converted value compares your result with widely cited morning reference ranges: about 300–1000 ng/dL (10.4–34.7 nmol/L) for adult men and about 15–70 ng/dL (0.5–2.4 nmol/L) for adult women. Being inside or outside these bands is a starting point for discussion, not a verdict — levels naturally fall with age, vary through the day, and must be read together with symptoms and other lab values.
Quick Conversion Reference
| ng/dL | nmol/L | Typical context |
|---|---|---|
| 15 | 0.52 | Lower end, adult female range |
| 70 | 2.43 | Upper end, adult female range |
| 300 | 10.41 | Lower end, adult male range |
| 500 | 17.34 | Mid-range, adult male |
| 1000 | 34.67 | Upper end, adult male range |
Assumptions and Limitations
- The calculator converts total testosterone units only; it cannot convert total to free testosterone or bioavailable testosterone.
- Reference ranges vary between laboratories, methods and assay platforms — always prefer the range printed on your own lab report.
- Testosterone is highest in the early morning and drops by afternoon; samples drawn late in the day can read 20–30% lower.
- Ranges shift with age: a level normal for a 70-year-old man may be low for a 25-year-old.
- The tool is for information only. A diagnosis of hypogonadism, PCOS or any other condition requires repeated measurements, free testosterone, SHBG, LH/FSH and clinical evaluation by a doctor.
If you also track other lab values in mixed units, you may find our HbA1c converter useful for the same reason: hemoglobin A1c is reported as a percentage in some countries and in mmol/mol in others.
Frequently Asked Questions
Can I use this converter for free testosterone results?
Only if your free testosterone is reported in ng/dL or nmol/L, which is rare. Free testosterone is usually given in pg/mL or pmol/L, and the conversion factor is different \(1 \text{ pg/mL} = 3.467 \text{ pmol/L}\) because the units are 1000 times smaller than those for total testosterone. Entering a free testosterone value here will produce a meaningless result, so check the unit line on your report carefully first.
Why did two labs give me different testosterone numbers?
Differences usually come from three sources. First, assay platforms (LC/MS versus immunoassay) can disagree by 10–20% or more. Second, sampling time matters: testosterone peaks around 8 a.m. and can drop 20–30% by afternoon, so guidelines recommend a morning draw. Third, illness, poor sleep, stress and certain medications temporarily shift levels. Always convert to the same unit before comparing, and judge trends only with samples taken under similar conditions.
Is my testosterone level normal for my age?
The typical adult male range of about 300–1000 ng/dL (10.4–34.7 nmol/L) applies mainly to healthy young men measured in the morning. Levels decline steadily with age — roughly 1–2% per year after 30 — so a value near 350 ng/dL may be unremarkable at 70 but low at 25. Reference ranges printed by your laboratory may also be age-adjusted. Discuss age-specific interpretation with your doctor rather than relying on a single generic range.
Can one low result mean I have low testosterone (hypogonadism)?
No. Clinical guidelines require at least two separate morning measurements showing low total testosterone, ideally confirmed with a free testosterone calculation, before hypogonadism is even considered. Symptoms such as fatigue, low libido or reduced muscle mass must also be present, along with supporting tests like LH, FSH and SHBG. This converter only translates units — it cannot diagnose anything. Please see an endocrinologist or urologist for evaluation.
What is the difference between total, free and bioavailable testosterone?
Total testosterone counts all hormone in blood, including the 60–70% tightly bound to SHBG and most of the rest loosely bound to albumin. Free testosterone is the small unbound fraction (about 1–2%) that is biologically active, while bioavailable adds the albumin-bound portion. A man can have normal total but low free testosterone when SHBG is high — common with obesity, ageing or thyroid issues. That is why SHBG is often tested alongside total testosterone.
How do I convert testosterone to or from ng/mL?
Some research papers and saliva tests report ng/mL instead of ng/dL. The relationship is simple: since 1 dL equals 100 mL, \(1 \text{ ng/mL} = 100 \text{ ng/dL}\). So to convert ng/mL to nmol/L, first multiply by 100, then divide by 28.842 — equivalently, divide the ng/mL value by 0.28842. A value of 5 ng/mL, for example, equals 500 ng/dL or about 17.34 nmol/L.