How to Use the Free Fasting Tracker (And Keep Your History)
By Brian Hupp ·
The free Fasting Companion Tracker needs no sign-up: pick a window, start the timer, and sessions save in this one browser as you go. The one step people skip is exporting a backup before clearing their browser or switching devices. Here's the whole tool, in order.
What's actually in the tracker
All five windows (12:12, 14:10, 16:8, 18:6, 20:4) are open from the start. There's no required order and no ranking, so picking 12:12 isn't a "lower tier" than 20:4, it's just a different number. You can switch windows or go back to an easier one at any time without losing anything already saved.
- Eating window schedule: a separate field for when your eating window starts each day. Changing it is just your own planning note, it never rewrites an active or already-saved session.
- Start and stop timer: a plain start/stop button, with a confirm screen that lets you adjust the stop time before saving.
- Session correction: while a session is active, an optional "Correct this session's times" field lets you fix a start time you forgot to log; the tracker rejects a corrected start time that falls after the current moment. The stop-time confirm screen has the same rule: you can nudge the stop time earlier or later, but not past the moment you're confirming it.
- Optional check-in note: a short free-text box, never required, attached to the session.
- History: every completed session, editable or deletable individually.
Starting your first session
Worked example
Say you pick 16:8 and want your eating window to start at noon. On the tracker, select the 16:8 tile, set "Eating window starts" to 12:00 PM, then press Start fasting whenever you actually stop eating the night before. The schedule field and the timer are independent: the schedule is just your plan, the timer tracks what actually happened.
When you're ready to eat, press Stop fasting. You'll get a confirm screen showing the stop time; adjust it if you actually broke your fast a few minutes earlier or later than when you pressed the button, then confirm. That session now appears in your history.
Browser-only storage: what that means for you
There's no account. Your window, schedule, and history are saved only in this one browser, on this one device, using your browser's local storage, and the browser controls whether that storage actually persists: it may be cleared by the browser itself, by low disk space, or by settings you don't directly control. That also means the data is tied to one browser profile. Switching browsers or devices doesn't delete your original data where it was, it simply doesn't follow you to the new one; opening the tracker in a different browser or on a different device starts with an empty history. Private/incognito windows are usually cleared automatically when you close them, so treat anything logged there as temporary. Export before you switch, clear site data, or rely on a private window, since none of those situations can be recovered afterward without an export taken first.
Exporting and backing up your data
The Backup and restore section has an Export data (JSON) button that downloads everything as one file. Treat this like a password manager export: boring until the day you need it. Export before clearing your browser's storage, before switching to a new phone or laptop, or just periodically if your history matters to you.
Worked example
You've logged three weeks of sessions on your laptop and are about to get a new one. Open the tracker, click Export data (JSON), save the file somewhere you'll find it (cloud drive, email to yourself, a USB stick), then set up the laptop and use Import on the new one. If you ever import that same file twice by mistake, already-present sessions are skipped, not duplicated.
If you lose your history
Being direct about this: if you never exported and your browser data gets cleared, that history is gone. There's no account to recover it from and no server copy anywhere. The storage-warning banner on the tracker page will tell you if storage isn't available at all in your current browser (common in some private-browsing modes); in that case the timer still works for that visit, but nothing will be saved afterward unless you export before leaving.
What this tracker doesn't do
There's no cross-device sync and no account, by design, this is a free, local-only tool. The "Guidance tier" card on the page is a static preview of a possible future paid feature; it isn't functional today and won't charge you anything. The tracker also doesn't collect or require any health screening, that's a separate, optional step: the free Fasting Readiness Quiz is educational information, not a medical clearance.
New to the window numbers themselves? See 12:12, 14:10, and 16:8: What Do Fasting Windows Actually Mean? first, or try the free tracker directly.
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About the author. Brian Hupp is a regular guy from Ohio who lost about 300 pounds with intermittent fasting after a rheumatoid arthritis diagnosis in late 2022. He is not a doctor or a nutritionist. Read his story: How I Lost 300 Pounds With Intermittent Fasting.