Classify sperm morphology by entering the percent and selecting the reported method (Kruger strict or WHO 6th). Add other semen values for a plain-language summary and notes on when to repeat testing or seek a review.
How this calculator works
- Inputs: morphology percent, method used (Kruger strict or WHO 6th), optional semen values (volume, concentration, total and progressive motility), days of abstinence, and hours to analysis.
- Outputs: morphology classification against the chosen standard, a plain-language interpretation, an overall semen summary if you provide more values, and notes on when to repeat testing or seek a review.
Methodology & limits
The tool compares your morphology percent with the cut-points used by the selected reporting standard on your lab report. If other semen values are entered, it summarises them and highlights patterns that commonly prompt a repeat test. Days of abstinence and transport time are used for context only.
Semen parameters vary between samples. One result is not a diagnosis (AUA/ASRM guideline). For personalised advice, see your clinician.
Frequently asked questions
Which method should I choose?
Match the method on your lab report. Many labs use strict criteria (Kruger). Some report to WHO 6th guidance. The calculator follows the method you select.
Is 4% considered normal?
Many strict-criteria reports use 4% normal forms as a lower reference point, but labs may differ (NICE NG257; WHO semen manual). Always interpret results in the context of the method on your report.
Does low morphology mean infertility?
Low morphology alone does not diagnose infertility. Clinicians interpret it with the other semen parameters and the couple's evaluation (AUA/ASRM guideline).
When should I repeat the test?
If the first semen analysis is abnormal, NICE recommends a repeat confirmatory test, ideally after 3 months to allow the sperm-production cycle to complete; severe sperm deficiency may be checked sooner (NICE NG257).
Do abstinence days or delays to analysis affect results?
Abstinence interval and time to analysis can affect semen measurements, so follow the laboratory's collection and transport instructions and check the collection details on your report (ASRM guidance; WHO semen manual).