What Is the Normal Sperm Motility Level?

Sperm motility refers to the percentage of spermatozoa in semen exhibiting progressive (forward) movement.

Sperm motility is generally classified into four grades: Grade 0 (d-grade): No motility—sperm are completely immotile; Grade I (c-grade): Non-progressive motility—sperm move but not forward (e.g., in circles or vibrating in place); Grade II (b-grade): Slow or sluggish progressive motility—sperm move forward slowly or with reduced vigor; Grade III (a-grade): Rapid, straight-line progressive motility—sperm move forward rapidly in a straight line.

Normal reference values are as follows: ≥25% Grade III (a-grade) sperm, or the combined proportion of Grade III (a-grade) and Grade II (b-grade) sperm ≥50%.

For normal fertility, the proportion of motile sperm should exceed 70%. A motile sperm percentage below 50% is considered abnormal—specifically, when the proportion of progressively motile sperm (a-grade and b-grade combined) falls below 50%, or when a-grade sperm alone constitute less than 25%. Complete absence of sperm motility is termed necrozoospermia.

Patients with low sperm motility should undergo seminal plasma analysis and detailed medical history evaluation to identify underlying causes—such as varicocele or genitourinary tract infection—and thereby determine the true etiology. Targeted treatment can then be initiated based on the identified cause.