Tool · Menstrual calendar

Interactive menstrual calendar

A practical reference to anticipate your upcoming periods, estimate the fertile window and identify the likely day of ovulation based on your usual cycle.

Used only to personalize your view. Not required.
Shown only on your screen. Never sent to any server.
Select the date when your last period began.
Use an average between 21 and 40 days. If your cycles vary, save several in your history.
Use the number of days your period usually lasts, typically between 2 and 10.
Where and how is your data stored?

This tool runs entirely in your browser. Nothing you type here is sent to a server, linked to your IP, email account or medical record.

  • Data is stored in the local storage (localStorage) of the browser and device you are currently using.
  • If you open this site from another browser or device, you will not see this information — there is no central record.
  • If you clear history / cookies / site data on this browser, the data is automatically deleted.
  • No one on the medical team can see what you log here. To share it during a visit, write it down or show it on screen.

If you want to delete everything this tool saved in this browser, use the button below. The action is immediate and cannot be undone.

How is it calculated?

The tool takes the first day of your last period, adds your average cycle length and projects the following dates. Ovulation is estimated 14 days before the next period, and the fertile window includes the five prior days, the ovulation day and one day after.

Why can it help?

It can help you recognize patterns, prepare better for a consultation about irregular cycles, orient the timing of pregnancy attempts or understand more clearly which phase of the cycle you are in.

Cycle history

If your cycles do not always last the same, save several values and use the average for a more realistic orientation.

You have not saved past cycles yet.

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