The free testosterone calculator that shows your exact percentile rank on a bell curve. See how your T level compares to men your age — anonymous, instant, and completely private.
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| Age Group | Low (<10th pct) | Average (50th pct) | Optimal (>75th pct) | High (>90th pct) |
|---|---|---|---|---|
| 20–29 | < 400 ng/dL | 620–680 ng/dL | 750–850 ng/dL | > 900 ng/dL |
| 30–39 | < 350 ng/dL | 550–620 ng/dL | 700–780 ng/dL | > 850 ng/dL |
| 40–49 | < 300 ng/dL | 490–560 ng/dL | 640–720 ng/dL | > 780 ng/dL |
| 50–59 | < 260 ng/dL | 430–510 ng/dL | 580–660 ng/dL | > 720 ng/dL |
| 60+ | < 220 ng/dL | 370–450 ng/dL | 520–600 ng/dL | > 660 ng/dL |
Reference ranges are based on NHANES data and published endocrinology literature. Individual lab reference ranges may vary. Values are for total testosterone tested in the morning.
Your testosterone value is converted to a z-score using the mean and standard deviation for men in your age group, drawn from NHANES population data and peer-reviewed endocrinology studies. That z-score is mapped onto a normal distribution curve to produce a percentile — the percentage of men your age with lower testosterone than you.
Normal ranges vary by age and lab. Most reference ranges span 300–1000 ng/dL, but "normal" doesn't always mean "optimal." Men in their 20s typically average 600–700 ng/dL, declining roughly 1–2% per year from age 30 onward. Symptoms of low T can appear at any level below your personal optimal.
Most physicians diagnose hypogonadism when total testosterone falls below 300 ng/dL. Some use 350 ng/dL as a threshold, especially when symptoms are present. Free testosterone below 50–65 pg/mL is also considered low. Always combine your number with how you feel — symptoms matter as much as the lab value.
Testosterone follows a circadian rhythm, peaking in early morning (7–10 AM) and dropping 20–30% by the afternoon. A reading taken at 3 PM may appear low even if your morning level is healthy. For accurate results and clinical comparisons, always test before 10 AM, ideally fasted or after a light breakfast.
Total testosterone measures all T in your blood. Free testosterone is the biologically active fraction not bound to SHBG or albumin — it's what your cells actually use. Total T is the standard first test. If total T is borderline low (300–400 ng/dL), checking free T can reveal whether actual deficiency exists, especially in men with elevated SHBG levels.
Your personal identity is never stored. When you hit Calculate, only anonymous aggregate data is used to power community statistics — no name, no IP address, no device ID. Nothing that could ever identify you.
Yes — within limits. Evidence-backed approaches include resistance training (especially compound lifts), adequate sleep (7–9 hours), maintaining a healthy weight, reducing chronic stress, optimizing vitamin D and zinc intake, and minimizing alcohol consumption. These can realistically raise levels by 10–20% but won't reverse true hypogonadism. For significantly low T, consult a men's health physician about TRT.