The WHO 2021 lower reference limits are: volume 1.4 mL, concentration 16 million/mL, total count 39 million, total motility 42%, progressive motility 30%, normal morphology 4%, vitality 54% and pH 7.2. They are the 5th centile of 3,589 fertile men, so a value below one means "in the bottom 5% of a fertile group", not "infertile". This checker shows each value as within or below that range, calculates total count from volume and concentration, and explains what each measure is. It doesn't diagnose anything.
Enter your results
Leave blank anything your report doesn't give. Decimals are fine. Total count is calculated from volume and concentration if you leave it empty.
The reference limits
The same numbers, for comparing by hand. They come from Table 2.1 of the WHO manual (one-sided lower reference limits, 5th centiles); pH 7.2 is the manual's consensus threshold rather than a centile. The app reads them from the same source file, and this page's copy is published at limits.json.
| Measure | WHO 2021 lower reference limit | What it is |
|---|---|---|
| Semen volume | 1.4 mL | How much semen the sample contained. Often low because of a short abstinence period or an incomplete collection. |
| Sperm concentration | 16 million/mL | Sperm per milliliter. The most variable number between samples from the same man. |
| Total sperm count | 39 million | Concentration multiplied by volume; the number of sperm in the whole sample. |
| Total motility | 42% | Share of sperm moving at all. |
| Progressive motility | 30% | Share swimming forward; the motility number clinicians look at first. |
| Normal morphology | 4% | Share with a typical shape under strict criteria. Low in every fertile man and variable between labs. |
| Vitality | 54% | Share alive. Mostly useful when motility is low. |
| pH | 7.2 or more | Acidity. Low pH with low volume can point to a blockage. |
How to use the result
- Read "below the reference range" as a description of one sample, not a diagnosis: it puts the value in the bottom 5% of a group of men who all conceived within a year.
- Check the abstinence window on your report. The WHO manual asks for 2 to 7 days; shorter lowers volume and count, longer lowers motility.
- Think back over the three months before the sample. Fever, illness, a heavy month or a hot tub habit can pull one result down, because sperm take about 74 days to develop.
- If anything is below the limit, the next step is a repeat test about three months later, same lab and same abstinence window, not treatment. If no sperm were found, ask for the repeat straight away.
- Take the report to the clinician who ordered it, or a urologist or andrologist if the result is severe or comes with a history that raises a flag.
What this tool doesn't do
It doesn't diagnose, score, or predict whether you can conceive. It doesn't cover DNA fragmentation or antisperm antibodies, which have no WHO reference limit. It doesn't know your partner's side of the picture, which matters just as much. The full explanation of every measure, why one result is noisy, and when to see a specialist is in the guide to reading your semen analysis.
Related
Sources
- World Health Organization. WHO laboratory manual for the examination and processing of human semen, 6th edition. Geneva, 2021.
- Boitrelle F, et al. The sixth edition of the WHO manual for human semen analysis: a critical review and SWOT analysis. Life, 2021.
- NICE. Fertility problems: assessment and treatment (NG257). 2026.
