Plan it, or let Datum plan it
Build a plan out of reusable templates, or answer seven quick questions (split, days, session length, goal, focus, equipment, and injuries) and Datum builds a complete plan for you to fine-tune.
iPhone · Private by default
Your training, tracked like data actually matters.
Datum is an iPhone workout tracker built around plans, plate math, and progress you can actually see, with your data stored on your device, not someone else's server.
iPhone only · iOS 18+ · Currently in beta
On-device storage
Your workouts live on your phone, not a company's server.
iCloud sync, opt-in
Off by default. Turn it on only if you want it.
Apple Health, both ways
Workouts and metrics sync in and out, automatically.
No ads, no account
Nothing to sign up for and nothing to sell.
Features
Built around how you actually train.
Log a set without losing your rhythm
Warm-up sets, drop sets, and supersets are built in, plus a plate calculator so you're not doing math between sets.
Cardio and classes, not just lifts
Log a class or a cardio-machine session as its own activity, live with a start/stop timer or after the fact. Stands alone, or drops into a strength session as a warm-up.
Your data, on your terms
Two-way Apple Health sync, iCloud backup you turn on yourself, and one-tap export to JSON whenever you want it.
Share plans with your training partner
Send a Plan or Template to another Datum user and they can pull it straight into their own library. No account or server in between.
Learn the moves and the method
A built-in glossary and a plain-language guide to five real training splits, so you're never guessing what a term means or which approach fits you.
Reports
Named for the data, built for the trend.
Every logged set feeds a set of reports that actually try to tell you something, not just restate your history back to you.
Estimated 1-rep max trend
Per exercise, once you've logged it more than once.
Personal records
Tracked automatically as you log, no data entry required.
Volume by muscle group
See where your training time is actually going.
Training volume × body composition
Shown side by side over 30d, 90d, 1y, or all time. These charts show what happened on the same days, not that one caused the other.
FAQ
Questions people actually ask.
Is my workout data private?
Yes. Workouts are stored on your iPhone. iCloud sync is optional and off by default, and even when it's on, it goes to your own private iCloud account, not a company server. The app itself uses no third-party analytics or tracking.
Does Datum work with Apple Watch?
Not yet. Datum is iPhone-only for now; an Apple Watch companion is a possible future addition, not built in v1.
Do I need to create an account?
No. There's no sign-up, no login, and no account system of any kind.
Does Datum work offline?
Yes. Your plans, workouts, and history are stored locally, so logging a workout doesn't need an internet connection. Apple Health sync, iCloud sync, and sharing a plan with another Datum user do need connectivity.
Is Datum free?
It's free during the current TestFlight beta. A simple subscription tier is planned for later; pricing hasn't been set yet.
Does Datum connect to Apple Health?
Yes, two-way. With your permission, it reads from and writes to Apple Health, including workouts, energy, heart rate, and body composition.
Datum is in beta on TestFlight.
Public beta access is opening soon. Join to get in as soon as a spot is available.