Total vs Free Testosterone: 6 Facts and a Calculator
TOTAL VS FREE TESTOSTERONE: 6 FACTS AND A CALCULATOR
Most lab reports show one testosterone number: total testosterone. What is free testosterone, then? But only a small part of it floats free in the blood. That free part is the one most experts think your body can actually use. So total vs free testosterone is not a small detail. It can change what your result means.
This guide explains what each number measures, when free testosterone matters, how it is measured, and why ranges differ between labs. It includes a calculator you can use with your own results. Every figure comes from a PubMed abstract listed at the end. For the protein that splits the two, see SHBG levels explained.
Total vs free testosterone in three numbers
Three numbers frame total vs free testosterone. Where total testosterone counts as low, where free testosterone starts in healthy men, and how often low total without low free caused symptoms.
Bottom of the harmonized total testosterone range
In healthy, non obese men aged 19 to 39, the harmonized range for total testosterone was 264 to 916 ng/dL (PMID 28324103).
Bottom of the free testosterone range in healthy men
With a standardized dialysis method, free testosterone in healthy non obese men ran from 66 to 309 pg/mL (PMID 36251328).
Men with new low testosterone who also had low free T
In obese men, only those whose total and free testosterone both fell, 27.3 percent, developed sexual symptoms (PMID 29855071).
Every figure on this page comes from a PubMed abstract listed at the end. The calculator gives an estimate with a published formula, not a lab result. This page is education, not a diagnosis.
What this guide covers
Total vs free testosterone: what each one measures and why they can disagree.
Free testosterone levels in healthy men, and why lab ranges differ.
When free testosterone matters, how to test it, and a calculator for your own numbers.
Not covered
Women. This page is about adult men.
Treatment decisions. A doctor reads these numbers with your symptoms and history.
Total vs free testosterone: what total testosterone measures
Total testosterone counts all the testosterone in your blood. That includes the part tightly bound to SHBG, the part loosely bound to albumin, and the small free part.
It is the first test doctors use. The Endocrine Society recommends a fasting morning total testosterone with an accurate assay, repeated to confirm a low result (PMID 29562364). A 2026 JAMA review says to draw the blood between 7 and 10 am, on at least 2 fasting samples (PMID 42207626).
A harmonized study pooled 9,054 men. It set the normal range for healthy non obese men aged 19 to 39 at 264 to 916 ng/dL (PMID 28324103). The JAMA review uses less than 264 to 300 ng/dL as low (PMID 42207626).
What is free testosterone?
Free testosterone is the part not attached to any protein. The free hormone idea says this unbound part is the one that enters cells and acts (PMID 42634762). Albumin bound testosterone lets go easily, so free plus albumin bound is often called bioavailable testosterone.
A 2026 study gave strong support to this idea. In 15 men with very high SHBG and failing testes, free testosterone was low and the brain was pushing hard with high LH and FSH. Yet 8 of them had total testosterone above 450 ng/dL, and 4 were above 916 ng/dL (PMID 42634762).
In this total vs free testosterone split, the body seems to follow free testosterone, not total. That is why a normal total can hide a real problem when SHBG is high.
Free testosterone levels and the normal range in healthy men
Free testosterone levels have no single normal range. Two recent studies show why, and why total vs free testosterone results must be read against your own lab.
A 2023 study measured free testosterone with a standardized dialysis method in 145 healthy non obese men. The range was 66 to 309 pg/mL, and 120 to 368 pg/mL in men aged 19 to 39 (PMID 36251328).
A 2026 study of 1,202 men used a different dialysis method. Its range for healthy young men was 184 to 749 pmol/L, about 53 to 216 pg/mL (PMID 40929374). Free testosterone fell 4.5 pmol/L per year of age, and a BMI of 30 lowered it by 14.4 percent.
| Study | Men | Range |
|---|---|---|
| Jasuja 2023 | Healthy non obese, all ages | 66 to 309 pg/mL (PMID 36251328) |
| Jasuja 2023 | Aged 19 to 39 | 120 to 368 pg/mL (PMID 36251328) |
| Walravens 2026 | Healthy non obese, 18 to 39 | 184 to 749 pmol/L, about 53 to 216 pg/mL (PMID 40929374) |
| EMAS definition | Low free T cut off | Under 220 pmol/L, about 64 pg/mL (PMID 20554979) |
Calculate your own free testosterone
Enter your total testosterone, SHBG and albumin from your lab report to see your own total vs free testosterone split. The calculator uses the Vermeulen equation, which matched the reference dialysis method closely in a 1999 study (PMID 10523012). The colour band compares your result with the EMAS cut off of about 64 pg/mL (PMID 20554979).
Free & Bioavailable Testosterone
Drag the sliders (or type) to enter your bloodwork and estimate free and bioavailable testosterone with the Vermeulen equation, a published formula. An estimate, not a lab result.
This is an estimate. A 2017 review argued that the binding models behind such formulas may not be fully accurate (PMID 28673039). For a bigger version with unit switching, open our free testosterone calculator or the free androgen index calculator.
When free testosterone matters more than total
The Endocrine Society recommends checking free testosterone when total is near the lower limit. The same applies when a condition changes SHBG (PMID 29562364). That is when total vs free testosterone really splits. The 2026 JAMA review names obesity and diabetes as common examples, because they lower SHBG (PMID 42207626).
The European Male Ageing Study shows why this matters. Over 4.3 years, 4.9 percent of men developed low total testosterone with normal free testosterone. Only 1.9 percent developed low total and low free testosterone (PMID 29855071).
| Symptom | Odds vs men with normal levels |
|---|---|
| Low sexual desire | 2.67x |
| Erectile problems | 4.53x |
| Fewer morning erections | 3.40x |
| Low total, normal free T | No link to new symptoms |
Men whose total testosterone fell but free testosterone levels stayed normal did not develop these symptoms. That group was mostly younger men with obesity and low SHBG (PMID 29855071).
How free testosterone levels are measured, and which methods to trust
| Method | How good | Source |
|---|---|---|
| Equilibrium dialysis | The reference method | PMID 35216721 |
| Calculated from total T and SHBG | Close to dialysis, except in pregnancy | PMID 10523012 |
| Free androgen index (100 x T / SHBG) | Not reliable in men | PMID 10523012 |
| Direct analog immunoassay | Not reliable, shifts with SHBG | PMID 10523012 |
A 2022 review recommends measuring total testosterone with mass spectrometry in a lab certified by the CDC HoST program. Free testosterone is ideally measured by equilibrium dialysis (PMID 35216721).
An earlier Endocrine Society statement warned that testosterone assays need proper standardization before normal values can be trusted across labs (PMID 17090633).
Total vs free testosterone on TRT
On TRT, total vs free testosterone still matters. Doctors use total testosterone to judge the dose, and free testosterone when SHBG is unusual (PMID 29562364).
Two men on the same dose can end up with different free testosterone levels if their SHBG differs. Androgens also lower SHBG, which raises the free share. More on that in SHBG levels explained.
Six facts about total vs free testosterone
1. Total counts all testosterone, free counts the unbound part. (PMID 42634762).
2. Normal total in healthy young men is 264 to 916 ng/dL. (PMID 28324103).
3. Free testosterone ranges differ a lot between labs. 66 to 309 pg/mL in one study (PMID 36251328), about 53 to 216 in another (PMID 40929374).
4. Check free testosterone when total is borderline or SHBG is off. (PMID 29562364).
5. Symptoms followed free testosterone, not total. (PMID 29855071).
6. Calculated free testosterone is useful; the free androgen index is not. (PMID 10523012).
Total vs free testosterone: frequently asked questions
What is the difference between total vs free testosterone?
Total testosterone counts all testosterone in the blood, bound and unbound. Free testosterone is only the unbound part, which is thought to be the active part (PMID 42634762).
What is a normal free testosterone level?
It depends on the lab. One standardized study found 66 to 309 pg/mL in healthy non obese men (PMID 36251328). Another found about 53 to 216 pg/mL in young men (PMID 40929374).
Which is more important, total or free testosterone?
Total testosterone is the first test. Free testosterone matters when total is borderline or SHBG is abnormal (PMID 29562364). In one study, symptoms followed free testosterone (PMID 29855071).
Can I have normal total but low free testosterone?
Yes, mainly when SHBG is high. In one study, men with very high SHBG had low free testosterone even with total above 916 ng/dL (PMID 42634762).
Can I have low total but normal free testosterone?
Yes, often with obesity and low SHBG. These men did not develop new sexual symptoms over 4.3 years (PMID 29855071).
How is free testosterone measured?
Best by equilibrium dialysis (PMID 35216721), or calculated from total testosterone and SHBG (PMID 10523012). Direct immunoassays and the free androgen index are not reliable (PMID 10523012).
What is bioavailable testosterone?
Free testosterone plus the part loosely bound to albumin. Both are thought to reach tissues, while SHBG bound testosterone does not.
When should total testosterone be tested?
In the morning, fasting, between 7 and 10 am, on at least 2 days (PMID 42207626).
Sources and further reading
Every figure on this page comes from one of the 12 papers below, checked against their PubMed abstracts on 26 October 2026. The pg/mL conversion of the 2026 range is our own (1 pg/mL is about 3.47 pmol/L). The calculator is an estimate with a published formula. Reference links are dofollow to support open science.
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More on testosterone labs
Four pages that sit next to total and free testosterone on a hormone panel.
Final Educational Note
This article is educational and is not medical advice. It explains what research says about total vs free testosterone in adult men. The calculator gives an estimate, not a lab result. A doctor should read your numbers with your symptoms, and you should not start or change any hormone on your own. More guides sit on the TRT and hormones hub and the bloodwork hub.
MuscleScience does not sell tests, hormones or medical services. Read more on the about page and in the full disclaimer.
