Health · Cycle check
Cycle Irregularity Checker
Enter your average cycle length, variation, and any symptoms to get a pattern verdict — and clear flags for when to speak to a GP.
Instant result
Plain-English why
Copyable takeaway
What this means
This tool checks cycle length against the 21–35 day typical range, variation between cycles, and flags symptoms that are worth discussing with a GP.
Formula used
Flags: cycle length outside 21–35 days, variation greater than 7 days between shortest and longest cycle, plus symptom-based GP referral flags.
Worked example
28-day average, 4-day variation, 6 cycles tracked, no additional symptoms — regular pattern. 18-day average, 12-day variation, spotting and severe pain — outside typical range with GP-referral symptoms.
Common questions
What is a typical cycle length?
The range considered typical is 21–35 days, with 28 days being the frequently cited average — but this is a population average, not a norm. Cycles that are consistently shorter or longer but stable can be entirely normal for an individual. Significant variation (more than 7 days between your shortest and longest cycles) is a better indicator of irregularity than length alone.
When should I see a GP?
Spotting between periods, pain that disrupts daily activities, missed periods (not explained by pregnancy or recent contraceptive change), and very heavy bleeding are all symptoms worth mentioning to a doctor regardless of cycle regularity. This tool flags these separately from pattern irregularity.
Plain-English summary
Enter your cycle data to get a verdict on whether your pattern looks regular and whether any symptoms warrant a GP conversation.
This section translates the result into a short, direct takeaway rather than leaving the page at a bare number.
Read the guide
How to track your menstrual cycle — and what to look for
Cycle tracking is most useful when you know what signals to record and what patterns actually indicate something worth discussing with a doctor.
Read the guideRelated instruments
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