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Fastn app icon — an amber progress ring with a flame at its centre, on black

Intermittent fasting tracker

Fastn

Intermittent fasting you’ll actually stick with.

A calm fasting companion: pick a protocol, watch your body move through its zones, and keep the streak going.

Download on theApp StoreGET IT ONGoogle Play
Platforms
iOS 17+ · Android 8+
Account
None
Works offline
Yes, including content
Protocols
12:12 through OMAD, plus custom
Fastn’s home screen: the fasting timer ring at 9 hours, the week’s streak and today’s fasting, eating and streak stats
Fastn’s home screen: the fasting timer ring at 9 hours, the week’s streak and today’s fasting, eating and streak stats

Screens

  • Fastn’s home screen: the fasting timer ring at 9 hours, the week’s streak and today’s fasting, eating and streak stats
    Fasting, finally simple.
  • Progress: total fasts, average, best streak and total hours, and a month of completed days
    Keep your streak alive.
  • Discover: the fasting phases, from Fed State to Fat Burning Zone, and tips and guides
    Every phase, explained.
  • A 30-day streak celebration with confetti
    Every milestone, celebrated.
  • Choosing a fasting protocol from 12:12 to OMAD, with 18:6 selected
    Your window. Your rules.

What it does

  • One honest ring

    Elapsed time, current zone and goal distance at a glance — the same ring on the Lock Screen and home screen.

  • Five fasting zones

    Fed, Fat Burn, Ketosis, Autophagy and Deep Ketosis, each with a short, sourced explanation.

  • Protocols and a builder

    Start on 16:8, move to 18:6 or OMAD when you’re ready, or design your own fasting and eating windows.

  • A streak worth keeping

    Milestone celebrations and a weekly rest day. It should feel earned, not fragile.

  • Weight and water, too

    Log both beside your fasts, set a goal for each, and review them on Progress.

  • A library to learn from

    Searchable fasting science, tips and nutrition guides, with bookmarks for what helps.

How it works

  1. 01

    Choose a protocol

    From gentle beginner windows to OMAD and extended fasts, or build a custom one.

  2. 02

    Start the fast

    One ring shows elapsed time, your zone and how far you are from your goal. A Live Activity keeps it in view.

  3. 03

    Complete it, grow the streak

    Finishing logs the fast and advances your streak, with a celebration at each milestone.

Privacy

What this app collects

Fastn has no account. Fasts, weight, water and settings are stored on your device.

  • No account or sign-in.
  • All health data (fasts, weight, water, notes) stays in an on-device database.
  • Fasting and nutrition content is bundled with the app — no content API calls.
  • The only third party is the subscription provider (RevenueCat), identified by a random device ID.
  • No advertising, no analytics SDK, no tracking, no App Tracking Transparency prompt.
  • Optional backups are exported by you to your own iCloud Drive or Google Drive.

A note on health

Fastn is a tracking and education tool, not medical advice. Intermittent fasting isn’t right for everyone — the app and the Terms of Use explain who should speak to a healthcare professional first.

Full detail: Privacy Policy · Terms of Use

Get Fastn

Download on theApp StoreGET IT ONGoogle Play

Questions? Contact support