Menstrual Cycle Calculator

Predict your next period and understand each cycle phase — menstrual, follicular, ovulatory and luteal — with this free menstrual cycle calculator.

Predict your next period

Enter your last period date and cycle length to predict your next 3 to 6 periods and plan ahead with confidence.

Understand your cycle phases

Each phase brings different energy, mood and physical changes. Knowing where you are helps you train, eat and rest smarter.