Private fertility tracking, explained

Most period trackers were built before privacy was a first-class concern. BedPost was not. This page walks through what cycle tracking in BedPost actually does, what it deliberately does not do, and how the fertile window estimate is generated.

What we collect, in order

The 6-screen cycle onboarding asks for the smallest amount of information we can use to give you a useful prediction:

• Last period start date. The single most important anchor.
• Typical cycle length. A default of 28 is fine; we tune it as you log.
• Typical period length. Used for the period band on the calendar.
• Optional: flow and symptom tags. Free-form, with a curated tag list. You can leave them blank.

That is it. We do not require basal body temperature, LH strips, or any device pairing to give you a useful estimate. If you want to log those signals manually you can — we will not stop you — but the core prediction does not depend on them.

How the fertile window is estimated

BedPost uses the standard calendar-based fertile window estimate: the model assumes ovulation occurs roughly 14 days before the next predicted period start, and shades the five days before plus the day of ovulation as the fertile window. As you log more cycles, the predicted next start date is refined using a moving average of your recent cycle lengths, and the fertile band moves accordingly.

This approach is intentionally conservative. Calendar estimates are a planning tool, not a clinical measurement. If you need higher confidence — for example because you are trying to conceive or trying to avoid pregnancy — you should layer in a method designed for that, like ovulation tests or fertility-awareness method (FAM) charting with a trained instructor. We say so in the app, on the cycle screen, and in our medical disclaimer.

What private actually means here

Privacy claims are easy to make and hard to verify. Here is what ours look like in practice:

• Encrypted at rest. Cycle dates, symptoms, and notes live in an encrypted Postgres column. Backups and snapshots inherit that encryption.
• No ad targeting on health data. We do not sell, rent, share, or licence your fertility or cycle data to advertisers, data brokers, or analytics partners. Period.
• Full erasure on request. Hit Delete my account in the app and a 6-provider cascade wipes you from our database, Stripe, Klaviyo, Mixpanel, RevenueCat, and the upstream backend within 30 days. See our data erasure guide for the full path.
• Export on request. You can email yourself a complete JSON + per-section CSV export of your data at any time, including every cycle log we have.
• No social features. There is no follow, no public profile, no leaderboard. There is nothing for the data to leak into.

What the cycle screen actually shows

The Journal tab calendar paints a per-cell phase tint (menstrual, follicular, ovulatory, luteal), an ovulation marker on the predicted day, period pips on logged flow days, and a brand-pink ring on today. Tap any day to see the symptoms, mood, and any activity you logged. The Cycle × Intimacy insight on the same tab is the only place where cycle data and activity data are joined; nothing else in the app reads from both.

Free vs Plus

Period tracking is free. The calendar, period history, flow and symptom logs, and basic next-period prediction are all on the free tier — and they always will be. BedPost Plus ($3.99/month or $39.99/year) unlocks the fertile window estimate, the Cycle × Intimacy insight, and the longer-range cycle insights. The split is intentional: we do not want a price tag between you and the basic ability to see when your period started.

What we will not claim

BedPost is not a medical device, not a contraceptive, and not a diagnostic tool. It does not detect or rule out pregnancy, sexually transmitted infections, hormonal disorders, or any clinical condition. The fertile window is an estimate, not a guarantee. If something feels off with your cycle, talk to a clinician. Our medical disclaimer spells this out in detail.