A date, not a guessing game.
See the estimated next start and a countdown when an estimate is available. During your period, find the current day count.
Understand your datesAvailable on Android · iPhone & iPad coming soon
A private period tracker, at your pace.
See where you are today and what’s estimated next. Log only what matters. Get on with your day.
- Free core tracking
- No account to journal
- 33 app languages
Useful from the first small step.
Last-period date and usual length are optional.
Your journal. Your choices.
See the privacy detailsProtected local records. Optional backup and sharing.
More useful answers. Fewer things to fill in.
You do not need a perfect diary. Start with what you know, save what you want to remember and keep estimates in perspective.
One thing is a check-in.
A mood, a symptom or a period start. Add the detail that helps you, and leave the rest.
Try a sample check-in. Choose one.
Example only; nothing is saved.
Your history stays useful.
Review recorded dates and prepare a free standard PDF for a conversation or appointment.
Make a useful reportSolid is what you recorded. Dashed is an estimate.
Rythena keeps the two apart, on Today and in Calendar. Try a sample period-start day and watch where the example estimate lands.
Sample cycle length
Sample period length
Example dates. In the app, the estimate uses the cycle length you enter or an eligible history average. It is always labelled Estimated, may be withheld, and is not a guarantee or birth control.
How the app calculates your next periodOctober 2026November
- Recorded
- Estimated
Recorded start: 3 October. Estimated next start: 31 October, 28 days later.
A little more clarity, screen by screen.
Actual App Store and Google Play listing artwork with synthetic examples. Android screenshots appear first. iPhone and iPad are coming soon. Swipe, drag or scroll to explore. Estimates are not guarantees.
Start small. Make it yours.
Begin with what you already know. Add more only when it helps.
Read the getting-started guideAdd what you know.
Enter a last period and usual length if you know them. Leave unknown answers blank.
Save what matters.
Start a period, choose a mood or note a symptom. End the tracked period when it really finishes.
See the bigger picture.
Check Today, review Calendar or prepare a free standard PDF. Explore Plus comparisons only if they help.
Optional Rythena Plus
A little support. On your terms.
Let someone you trust see only the summary you choose. Keep the rest of your journal yours.
- Private invitation, matching verification and your approval.
- Separate choices for cycle, fertility estimates and saved mood.
- Read-only partner view. No second Plus subscription.
Pause or reduce sharing for free. Offline revocation may remain pending; previously seen or copied information cannot be recalled.
Your questions. A clearer next step.
All 10 app guides- Getting startedHow to track your period without logging everythingStart a simple period journal in Rythena: save a start date, end the period when it finishes and add only the observations that matter to you.3 min
- Cycle datesPeriod countdown: see the estimated date, not just a numberUnderstand days until your next period, a period-day counter and what to do when an estimated date passes in Rythena.3 min
- Privacy & sharingWhat to look for in a private period trackerUnderstand Rythena's local journal, optional encrypted backup, sharing controls and the difference between no-account tracking and online services.3 min
- Privacy & sharingA period tracker for couples, with sharing on your termsUse Rythena Partner mode with private invitations, owner approval and separate sharing permissions. Viewing is free; owner publication requires Plus.3 min
- Your journalA period mood tracker with room for your own wordsUse Rythena's illustrated mood choices, frequent ordering and optional notes without assuming your cycle explains how you feel.3 min
- Your journalMake a period tracking PDF report for an appointmentPrepare and review a free standard period-tracking PDF in Rythena, choose useful dates and keep control of what you share.3 min
A little understanding goes a long way.
Explore all 20 articlesCycle length vs period length: two numbers worth separating
A 28-day cycle and a six-day period can both describe the same person. Learn which number shapes each part of Rythena's calendar.
A mood journal works better when the words actually fit
Move beyond happy or sad with specific mood choices, illustrated labels and a small check-in routine in Rythena.
Period tracker partner sharing: agree on the boundaries first
Use a simple conversation checklist before connecting Rythena Partner mode: purpose, permissions, support preferences, notifications and when to pause.
The things you want to know.
Short answers here. A practical guide when you want the detail.
Can I track my period without an account?
Yes. Rythena’s core journal works without an online account. Optional backup, sync and partner services have separate setup and data flows.
Learn moreHow does the app calculate my next period?
Choose an entered usual cycle length or an eligible history average. Today labels the date Estimated, and calculation details explain the basis.
Learn moreDoes my period keep counting after I start it?
An explicitly started ongoing period continues until you record its real end. The day counter does not invent individual daily flow observations.
Learn moreIs Rythena free, or do I need Plus?
The journal, Calendar, full history, reminders, raw export and standard PDF remain free. Plus adds extra comparison, report, sync and owner-sharing tools.
Learn moreCan I share my cycle with a partner?
If you choose. Owner creation/publication needs Plus; the recipient’s read-only view does not need another subscription. You approve the connection and each scope.
Learn moreAre the ovulation and fertile dates confirmed?
No. They are optional calendar estimates, subject to eligibility rules. They do not confirm ovulation and must not be used as birth control.
Learn moreCan I track symptoms if my periods are irregular?
Yes, you can keep observations and history. Forecasts may be withheld when the app cannot support an estimate. Tracking does not diagnose the cause.
Learn moreCan I save just a mood or one symptom?
Yes. Check-ins are optional and can be one thing. Choose the observation that matters to you, then save the entry.
Learn moreMake space for your actual day.
A clear period view. A small check-in. A journal that stays yours.
Available now on Google Play. iPhone and iPad are coming soon.
- Start with the free journalPeriod tracking, Calendar, full history, reminders and a standard PDF. No online account needed for core tracking.
- Choose Plus when it helpsDescriptive comparisons, richer reports, automatic encrypted sync and owner partner sharing. Plans and localised prices in the app.
Subscriptions are optional and auto-renew at the displayed store price until cancelled. Read the price and terms before purchasing.