Hormones

Prolactin unit converter

Pituitary hormone (milk production, pituitary disorders)

Also known as: PRL, Lactotropin, Luteotropic hormone, Prolactine, Prolactina, Prolattina

Converter

Enter a value in any unit and all other units fill in.

ng/mL = µg/L mIU/L µg/dL ng/dL

Worked example

12.5 ng/mL (middle of the reference range) = 265 mIU/L

Conversion formulas

mIU/L	mIU/L = ng/mL × 21.2	ng/mL = mIU/L × 0.04717
µg/dL	µg/dL = ng/mL × 0.1	ng/mL = µg/dL × 10
ng/dL	ng/dL = ng/mL × 100	ng/mL = ng/dL × 0.01

Reference range

Unit	Adults	Men	Women
ng/mL = µg/L	0 – 25	0 – 20	0 – 25
mIU/L	0 – 530	0 – 424	0 – 530
µg/dL	0 – 2.5	0 – 2	0 – 2.5
ng/dL	0 – 2500	0 – 2000	0 – 2500

Source: MedlinePlus (NLM): Prolactin blood test · Last reviewed: 2026-10-14

Note from the source: Men below 20 ng/mL, non-pregnant women below 25 ng/mL (MedlinePlus)

Frequently asked questions

How do I convert Prolactin from ng/mL to mIU/L?

mIU/L = ng/mL × 21.2. In the other direction: ng/mL = mIU/L × 0.04717.

What is the reference range of Prolactin?

For adults the range is 0 – 25 ng/mL (MedlinePlus (NLM): Prolactin blood test). Reference ranges differ between laboratories and partly by sex and age; use the range printed on your lab report.

Which units are used for Prolactin?

Common units are ng/mL, mIU/L, µg/dL, ng/dL.