Work out cycle length average instantly with clear inputs, formula shown and shareable results.
Averages the cycle lengths you have recorded, measures their spread and projects the next period from the last start date.
Cycle statistics
Average = sum of cycle lengths / number of cycles; variability = longest - shortest; next period = last start date + average length
Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
Adult cycles of 24 to 38 days with year-to-year variation under 9 days are considered regular.
At least three, and ideally six to twelve, before drawing conclusions about regularity.