Track your period. Full stop.
A calendar, a guess, a pink flower. They log the days and hand you nothing you can actually train on.
Cycle tracking, meet the barbell
Lift with your cycle,
Lift with your cycle,
not against it.
Ferrabelle is the wellness app that knows your cycle and your barbell. It forecasts your strongest training days by cycle phase, so you plan the heavy lifts for when your body is built to move them.
Free to start. Fe+ arrives with the mobile apps.
Privacy-first. No ads, no trackers, never sold.
Proof, not promises
Accuracy you can check.
Most apps say "smart predictions" and leave it there. We replayed Ferrabelle's real prediction engine against a public research dataset of 1,665 cycles from 159 women: 3,282 scored predictions, each made before the period arrived. Median miss: one day — and like-for-like, 12% ahead of the calendar method (1.82 vs 2.08 days mean error).
1 day median prediction error
76% within 2 days
3,282 real predictions scored
Grounded in published research on 600,000+ cycles, validated on data our engine was never tuned on, and updated whenever the engine changes. Read exactly how we measure it →
Ferrabelle is not a medical device and is not a contraceptive. Predictions can be wrong.
Why we exist
Every other app tracks your period.
Every other app tracks your period.
Ferrabelle trains with it.
Your cycle is not a problem to manage. It is a performance signal you have never been able to use. Until now.
Knows your lifts too.
Log the barbell alongside the cycle. Ferrabelle connects the two and learns how your strength moves with your hormones.
Forecasts your strong days.
For many lifters, the strongest days cluster in a window. Ferrabelle learns your pattern and points at it in advance, so you can plan the heavy lifts.
How it works
Three taps in. A training edge out.
Log your cycle and your lifts
A few taps a day. Period, sleep, how the session felt, what you moved. No spreadsheets, no judgement.
Ferrabelle learns YOUR body
The engine calibrates to you, not a textbook average. Every cycle sharpens the forecast for the next one.
Get your Fe Score and strong-day forecast
One readiness number every morning, plus a look ahead at the days your body is primed to hit the heavy stuff.
The Fe Score
One number answers one question. Push, or rest?
Every morning Ferrabelle fuses where you are in your cycle with your sleep, your stress, and how well you recovered, then hands you a single readiness score from 0 to 100. No graphs to decode at 6am. Just the call.
- Cycle phase
- Sleep
- Stress
- Recovery
Ferrabelle is a training and wellness companion, not a medical device and not a contraceptive. It does not provide medical advice, and predictions should not be used to prevent or achieve pregnancy.
0 Fe Score
You are primed to push today.
Phase training forecast
Know your strong days before they arrive.
For many lifters, PRs cluster in the follicular window. Ferrabelle learns whether that is true for you and maps the week ahead so you plan the heavy lifts there and back off when your body wants a lighter touch.
Deload, period likely Mon
Easy, listen in Tue
Building Wed
Solid day Thu
Peak strength Fri
Go for a PR Sat
Steady volume Sun
Menstrual Follicular Ovulation Luteal
Side by side
Pick the app that can prove it.
The others are good at what they do. None of them were built for the woman under the bar.
| Feature | Ferrabelle | Flo | Clue | Wild.AI | WHOOP / Oura |
|---|---|---|---|---|---|
| Set-by-set lifting log with PR-by-phase | ✓ | — | — | — | — |
| Readiness score that shows its math | ✓ | — | — | — | black box |
| Publishes prediction accuracy (dataset, method, number) | ✓ | — | — | — | — |
| Works without buying hardware | ✓ | ✓ | ✓ | ✓ | — |
| Price | Free today · Fe+ with the mobile apps | ~$50/yr | ~$40/yr | ~$64/yr | $199+/yr or a $300+ ring + $5.99/mo |
Based on each product’s published features and pricing as of mid-2026. “—” means not offered or not published. WHOOP and Oura are excellent hardware; they solve a different problem.
Your data, locked and yours.
Privacy, front and center
Your body’s data stays yours.
Tracking your cycle takes trust. In a post-Roe world that trust is not a nice-to-have, it is the whole point. So we built Ferrabelle to protect you first and impress you second.
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Never sold. Never rented.
Your cycle and your lifts are not a product we auction to advertisers. That is a promise, not a setting.
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No ad trackers, ever
No third-party ad SDKs riding along in the app to leak what your body is doing. None.
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Built to Washington’s My Health My Data Act
Engineered around one of the strictest health-privacy laws in the country, and treated as the product, not an afterthought.
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Export or delete everything, anytime
It is your body and your data. Take it with you or wipe it for good, on your terms, whenever you want.
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No AI reads your body
Predictions come from a transparent statistical engine on our own servers. No LLMs, no black boxes, and we publish exactly how accurate it is.
Read our Privacy Policy, our Consumer Health Data Privacy Policy, how we measure accuracy, and how to delete your data.
Why this exists
Built for one lifter first.
Ferrabelle didn’t start as a startup. It started as an app built for exactly one user: Steffany — a lifter who was tired of cycle apps that treated her training like it didn’t exist.
Every feature is here because she actually used it. The barbell log. The weight-on-cycle overlay. A readiness score with its math on the table. Predictions that had to survive being checked against real life, every month.
Then we opened the doors. It’s still built the same way: for the woman under the bar, one honest feature at a time.
— Steffany & Chris · Cobblewright LLC · Washington
The door is open
Start free today.
Ferrabelle is live. Free to start, works beautifully on your phone’s browser, and your data is yours from day one. The iOS and Android apps are next.
Open Ferrabelle — free
No card. No ads. Export or delete anytime.