What Fredrick is.
Fredrick is a private, on-device iPhone app for following your partner's menstrual cycle — set up together, with her consent. It shows what phase she's in and when her period is likely, always as honest date ranges, collects no data (no account, no servers), and costs $1 a month.
The short version
Fredrick is built for the partner — the boyfriend or husband — rather than the person whose cycle it is. The idea is small on purpose: one calm glance a day so you can show up with patience instead of surprise. It doesn't try to explain her feelings back to her, and it isn't a tool for tracking anyone secretly. It works best when you set it up together.
- What it isA private period tracker built for the partner, not the patient.
- PlatformiPhone (iOS). Lives entirely on your device.
- Price$1 a month, with a 7-day free trial. No tiers, no ads, no data sales.
- DataOn-device only — no account, no servers. App Privacy label: "Data Not Collected."
- PredictionsHonest date ranges that tighten over time — never a single fake-precise date, and never contraception.
- ConsentDesigned to be set up together, with her. It actively discourages covert tracking.
What it does
Three things, done calmly — nothing you don't need:
- Honest ranges. Fredrick predicts her next period as a range and tightens it as it learns her cycle. When it isn't sure yet, it says so.
- A little biology each day. One short card on what's happening hormonally and what it can mean for her mood and energy — with a tap for more when you're curious.
- Quiet heads-ups. An optional, low-key nudge before her period and the premenstrual window — a good moment for extra patience, with nothing dramatic on your lock screen.
Privacy, as architecture
Menstrual data is some of the most sensitive there is, so Fredrick is built to collect none of it. Every date, note, and prediction stays on your iPhone. There's no account to create, no server to breach, and nothing to sell — because there's nothing collected in the first place. If you want the full reasoning, read how privacy-first period tracking works.
Consent, built in
Fredrick works best set up together, with her. What you learn is here to help you be more patient and mindful — not to explain her feelings back to her, and never a way to track someone without their knowledge. That principle shapes the product and the copy throughout.
A note on the name: this Fredrick is unrelated to an older app that once used the same name with "manage her"-style marketing. This one is the opposite by design — consent-first, private, and built for shared understanding.
How it compares
Against feature-rich shared-mode apps like Flo for Partners, Fredrick trades some breadth for a guarantee: your data never leaves the device. If you'd like the fuller picture, see the guides on period trackers for men and period trackers for partners, which compare the main options honestly.
Understand her cycle. Be a better partner.
Private, consent-first, and honest — coming soon to iPhone.
Coming soon on the App Store →Frequently asked questions
What is Fredrick?
Fredrick is a private, on-device iPhone period tracker built for the partner. It shows what phase she's in and when her period is likely — as honest ranges — with no account, no servers, and nothing collected. It costs $1 a month with a 7-day free trial.
Who is Fredrick for?
The partner — the boyfriend or husband who wants to understand his partner's cycle so he can be more supportive. It's meant to be set up together, with her.
How much does Fredrick cost?
$1 a month, after a 7-day free trial. No tiers, no ads, and no data sales.
Does Fredrick collect any data?
No. Everything stays on your iPhone — there's no account and no server, so nothing is uploaded, synced, or sold. Its App Store privacy label reads "Data Not Collected."