Where is my menstrual cycle data stored?

Cycle settings, period days, symptoms, mood and notes are stored in localStorage on this device and browser. Clearing browser storage removes them.

How are next period and fertile dates estimated?

The tracker uses the cycle length you choose and, when available, the intervals between logged period starts. Estimates can differ from your actual cycle and are not medical advice or birth control.

Can a menstrual cycle tracker diagnose a health condition?

No. This tool is for personal organization only. It cannot diagnose, treat or rule out a health condition.

A calmer way to notice your rhythm

Menstrual Cycle Tracker Online

Q: Is this menstrual cycle tracker free to use online?

Yes. The tracker is free, works without an account, and saves your entries locally in your current browser.

Q: Does this period tracker work offline?

After the page and its local assets have loaded, the tracker itself can be used without sending cycle entries to a server. Your browser must allow localStorage.

Log period days, flow, symptoms and mood in a beautiful monthly calendar. See gentle estimates at a glance, without creating an account.

Offline-friendly — your entries stay in this browser

Startyour tracker

Your cycle rhythmAdd your last period

A date is all you need to create your first private forecast.

Next periodNot setAdd a start date

Cycle pattern28 daysYour starting estimate

Tracked cycles0Based on logged starts

Period estimateAdd a start date

Fertile window estimateNot available yet

Ovulation estimateNot available yet

Logged periodPredicted periodFertile estimateHas entry

Gentle insightYour personal pattern will appear as you log period starts.

Daily check-in

How was this day?

Period flowChoose one

SymptomsSelect any that fit

MoodOptional

Notes Only visible on this device

How to use this menstrual cycle tracker

Start with the information you know, then add short daily check-ins when they are useful. You are always in control of what you record.

Add your starting pattern

Enter the first day of your latest period plus your usual cycle and period lengths.

Log days that matter

Select a date to save flow, symptoms, mood or a private note. You do not need to fill every field.

Notice, do not diagnose

Use calendar colors and estimates as a personal reference, not as a medical conclusion.

Health note: Cycle predictions are estimates and can be inaccurate, especially when cycles are irregular. Do not use predicted fertile dates as contraception. This tracker does not provide medical advice, diagnosis or emergency guidance. Contact a qualified healthcare professional about pregnancy concerns, unusual bleeding, severe pain or other symptoms that worry you.

Menstrual cycle tracker FAQ

Helpful details about privacy, offline use and the estimates shown in this online period calendar.

Is this menstrual cycle tracker free to use online?

Yes. It is free and does not require an account or subscription. Enter a recent period start date and you can begin tracking immediately.

Does this period tracker work offline?

The calendar and tracker logic run in your browser. After this page and its local assets have loaded, you can continue logging without sending your cycle entries to a server. The GA4 analytics tag, like other pages on this website, may only load when internet access is available.

Where is my cycle information stored?

Your settings, period flow, symptoms, mood and notes are saved in localStorage in this browser on this device. There is no tracker account or cloud sync. Clearing site data, switching browsers or using another device will not carry entries over, so export a backup if needed.

How are the next period and fertile window estimated?

The tracker starts with your chosen cycle length. When you log multiple period starts, it can average valid cycle intervals to refine the estimate. Ovulation is estimated around 14 days before a predicted period, with a broader estimated fertile window. Real cycles vary, so these dates are not suitable for contraception or diagnosis.

Can I use this menstrual cycle calendar if my periods are irregular?

You can use it to organize observations, but future dates may be less reliable when cycle lengths vary. Your logged days remain useful as a personal record even when predictions are uncertain.

How do I remove or back up my data?

Use “Export data” to download a JSON backup. Use “Clear tracker” to permanently remove this tool's saved cycle data from localStorage in the current browser.