Frequently asked questions
How accurate are predictions further into the future?
Less accurate the further out they go — small natural variations in cycle length compound over several cycles, so the first 1-2 predicted dates tend to be more reliable than the 5th or 6th.
What if my actual cycle length varies a lot?
Track your last several cycles and use the average — or check back regularly and re-enter your most recent period start date for a refreshed prediction.
This calculator provides estimates for general informational purposes only and is not medical advice.