A period tracker for the partner

Understand her cycle.
Be a better partner.

Fredrick quietly tells you where she is in her cycle, when her period is likely, and what the week can mean — so you can show up with patience instead of surprise.

Coming soon on theApp Store iPhone · launching soon
Everything stays on your iPhone. No account, no cloud, no tracking.
Fredrick's Today screen — Day 15, Luteal phase, with the next period shown as a range
19:07
Monday, 20 July
Day 15
Luteal phase
Period likely 1–5 Aug
Fredrick is still learning her cycle — the range will tighten over time.
TodayLearn more ▸
Progesterone rises after ovulation, then both hormones drop sharply in the last few days — the withdrawal that triggers the period and most PMS.
For many people this is when irritability, low mood, or tiredness peak, and stressful things can feel bigger and stick longer. It eases once the period starts.
Log period started today
Today
Cycle
Log
Built for the partner, not the patient — you track, together, with her.
What Fredrick does

Three things, done calmly. Nothing you don't need.

Most people who want this track nothing today. So Fredrick stays small on purpose — one glance a day, and a little more understanding each time.

Honest ranges, never fake dates

Real cycles vary — so Fredrick predicts her next period as a range and tightens it as it learns hers. When it isn't sure yet, it says so.

A little biology each day

One short card tells you 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, deniable nudge before her period and before the premenstrual window — a good moment for extra patience, no drama on your lock screen.

Why it helps

A little awareness changes how you show up.

You don't need to become an expert. Simply knowing the rhythm of her cycle turns guesswork into understanding — and understanding into better moments, together.

Better timing

Plan the big conversations, the trips, and the surprises for when she's most likely to have the energy for them — and ease off when rest matters more.

Fewer misreads

A quiet week isn't always about you. Knowing what her body may be moving through helps you meet a hard day with patience instead of taking it to heart.

Feeling like a team

Being tuned in — instead of caught off guard — quietly says you're paying attention. Small awareness, felt as real care.

Less friction

See the week coming and you can be gentle before it's needed — heading off the small conflicts that only ever came from being surprised.

Privacy, not as a promise — as architecture

Her cycle is nobody's business but yours.

Menstrual data is some of the most sensitive there is. Fredrick keeps every date, note, and prediction 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.

App privacy
Data Not Collected
Account requiredNone
Cloud storageNone
Third-party trackersNone
Export & delete anytimeYes
Respect, built in

For your understanding — never against her.

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.

“Late in the cycle the brain's threat response runs a little hotter and hard moments stick longer — hormones, not character. This is for your understanding, never a thing to say to her.”

— from Fredrick's luteal-phase note
Simple, honest pricing

One dollar a month. That's the whole thing.

No tiers, no upsells, no ads. Try it free for a week and keep it only if it earns its place.

$1/month
7 days free, then $1/month
  • Predictions from her real cycles, as honest ranges
  • Gentle heads-ups before her period and the premenstrual window
  • A daily line on what's happening, and what it can mean
  • Everything on-device, forever
Coming soon on the App Store
Billed through your Apple ID. Auto-renews until cancelled in iOS Settings. Payment is handled by Apple — Fredrick never sees it.
Almost here

Be first to know when Fredrick launches.

It's coming to iPhone soon. Until then, the questionnaire that shaped it is still open — tell us what matters most to you.

Coming soon on theApp Store
Questions

Good things to ask.

Is this for tracking someone without them knowing?+

No — and Fredrick is built to discourage exactly that. It works best when you set it up together, and the predictions are only as good as the dates she shares with you. The app frames everything as shared understanding, with her consent.

Does my partner need to install anything?+

No. Fredrick lives entirely on your phone. You enter her recent period start dates — ideally together — and it takes it from there. There's no companion app to manage in this first version.

Where is the data stored?+

Only on your iPhone. There's no account and no server, so nothing is uploaded, synced, or shared. You can export or delete everything at any time from Settings.

Can I rely on it to avoid or plan a pregnancy?+

No. Calendar predictions are estimates, and ovulation timing varies too much between cycles to be used as contraception or for conception. Fredrick says so wherever fertility comes up. For anything medical, talk to a healthcare professional.

Why a dollar a month?+

It keeps the app honest and independent — no ads, no data sales, no pressure to grow engagement. A dollar covers its keep, and the 7-day free trial lets you decide before you pay a cent.