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Period Tracker

Log your periods on a calendar and see your next period, fertile window and cycle patterns. Your entries stay on this device. Nothing is uploaded, and no account is needed.

    PeriodExpected periodFertile windowOvulation (estimate)

    Your cycle lengths

    Coming up

      Settings and your data

      Your entries are saved only in this browser on this device. They are never uploaded or sent anywhere, and clearing your browser data erases them, so download a backup now and then. Predictions are estimates based on your own history. Cycles vary naturally, so treat the dates as a guide, not a guarantee. This tool is not medical advice and is not a method of contraception. If your cycles are very irregular, very painful or heavy, or you have any worries, please talk to a healthcare provider.

      About this tool

      Period Tracker helps you record the start of your periods and estimate when the next one is likely to begin. Seeing your own pattern over a few months makes it easier to plan ahead, and to spot changes that are worth mentioning to a doctor.

      It works from the dates and cycle length you give it. Cycles vary from person to person and from month to month, so treat the dates as estimates.

      How to use it

      1. Enter the first day of your last period.
      2. Enter your usual cycle length, if you know it, and how many days your period usually lasts.
      3. Read the estimated dates for your next period.
      4. Update the dates each cycle so the estimates stay useful.

      Example

      If your last period began on the 1st and your cycle is usually 28 days, the tool estimates that your next one will start on the 29th, and shows the days your period is likely to last.

      Tips

      • Cycle length is counted from the first day of one period to the first day of the next.
      • Stress, illness, travel and many other things can change your cycle.
      • Write down anything unusual, such as very heavy bleeding or severe pain, and speak to a health professional about it.

      Questions people ask

      How is the next period date worked out?

      It adds your cycle length to the first day of your last period.

      What is a normal cycle?

      Cycle lengths vary. Many adults fall somewhere between about 21 and 35 days. If your cycle suddenly changes, or you are worried, speak to a doctor.

      Can I use this to prevent pregnancy?

      No. It gives estimates only and is not a method of contraception.

      Is my data stored?

      Check the privacy information on the page. The tool works from the dates you enter.

      For general information only. This tool is not a medical device and does not replace advice from a doctor or other health professional. It cannot be used to avoid or achieve pregnancy.