Free tool
Testosterone Unit Converter
Total testosterone
UK reference ranges usually run from roughly 8 to 30 nmol/L.
1 nmol/L = 28.84 ng/dL
Free testosterone
Calculated free testosterone is typically reported in pmol/L in the UK.
1 pmol/L = 0.2884 pg/mL
Oestradiol (E2)
Often monitored on TRT alongside testosterone.
1 pmol/L = 0.2724 pg/mL
nmol/L to ng/dL: the quick reference
Most confusion about testosterone numbers comes from mixing two unit systems. UK labs report total testosterone in nmol/L, and a result of 15 sounds low next to a US forum post quoting 433, but they are the same level. Multiply nmol/L by 28.84 to get ng/dL, or divide to go back.
- 8 nmol/L ≈ 231 ng/dL (the level below which UK guidance treats deficiency as likely)
- 12 nmol/L ≈ 346 ng/dL (the upper edge of the UK grey zone)
- 15 nmol/L ≈ 433 ng/dL
- 20 nmol/L ≈ 577 ng/dL
- 30 nmol/L ≈ 865 ng/dL
Free testosterone follows a different conversion: pmol/L × 0.2884 = pg/mL, so 300 pmol/L is about 87 pg/mL. If you only have total testosterone and SHBG, our free testosterone calculator estimates the free figure for you.
A converted number still needs context. Testosterone peaks in the morning, so time of day matters, and the same total can mean very different free levels depending on SHBG. Our guide to how low testosterone is diagnosed in the UK covers what the thresholds mean in practice.
FAQs
Your TRT questions, answered.
How do I convert testosterone from nmol/L to ng/dL?
Multiply by 28.84. So 15 nmol/L is about 433 ng/dL. To go the other way, multiply ng/dL by 0.0347 (or divide by 28.84).
Why do UK and US labs use different units?
UK and most European labs report in SI units (nmol/L and pmol/L), which count molecules. US labs report mass per volume (ng/dL and pg/mL). Both describe the same amount of hormone, so a result isn't higher or lower in one system, it's just written differently.
What is a normal testosterone level in ng/dL?
The UK diagnostic thresholds of 8 and 12 nmol/L work out at roughly 230 and 350 ng/dL. Levels above 15 nmol/L (about 430 ng/dL) make deficiency unlikely. Our guide to TRT in the UK explains how those thresholds are used.
Does this tool calculate free testosterone?
No, it only converts units. To estimate free and bioavailable testosterone from your total testosterone, SHBG and albumin, use our free testosterone calculator.
Don't have your numbers yet?
Our at-home blood tests report total testosterone, SHBG and calculated free testosterone, reviewed by a GMC-registered doctor.
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