Support article
When is my period due
A period due date is simply the best estimate for when the next cycle should start. The stronger your recent rhythm, the more useful that date becomes.
Article body
Answer the search intent clearly, then guide the user back into the calculator flow.
A due date is a timing anchor
#A due date is not a medical promise. It is a planning estimate based on the rhythm you usually see from one month to the next.
That single date is useful because it helps you see whether you are still in your normal window or already moving outside it.
The estimate improves with better inputs
#These three pieces of information usually create the cleanest estimate. If one of them is missing, the date becomes less specific.
- The first day of the last period
- Your usual cycle length
- Recent pattern changes like travel, stress, or illness
Switch tools when the question becomes more specific
#If your period feels late, move into the late period calculator. If your monthly rhythm changes often, move into the irregular period calculator for a wider arrival window.
See whether your period is due soon
The homepage calculator gives you the due date, fertile timing, and next anchor in one view.
Start with the broad monthly forecast for your next period, ovulation, and fertile window.
FAQ
Cover the follow-up questions people usually have around this topic.
What does period due mean?
Your due date usually means the estimated first day of the next period based on your recent cycle pattern.
What information helps estimate a due date?
People usually look at the first day of the last period and the average cycle length from recent months.
When is a range better than one date?
If your cycles move around a lot, a date range is more useful than one exact day.
Reviewed guidance
Date-estimate pages should show where the timing logic comes from
Next-period estimates are most useful as educational forecasts built from the first day of the last period and recent cycle length. Visible sources make the planning boundary clear.
Office on Women's Health: Your menstrual cycle
Cycle basics, first-day counting, and when irregular timing deserves extra attention.
Open official sourceNHS: Missed or late periodsPlain-language guidance on common causes of late or missed periods and when to seek care.
Open official sourceOffice on Women's Health: Period problemsPatient guidance on missing periods, irregular timing, and symptom-led escalation.
Open official source