FastingWindow is a simple, no-account intermittent fasting tracker. Tap to start a fast, watch the dial fill as the hours go by, and see your body move through its natural fasting stages, from digestion to fat burning to deep ketosis.
Features
Live fasting timer
An apricot dial fills as your fast goes on. Under it you’ll see how long you’ve been fasting and how much time is left, then the stage you’re in, a five-color bar showing how far through the stages you’ve come, and a note on what your body is doing. Between fasts, it counts down to your next one.
Body stage tracking
FastingWindow tracks where your body is in the fasting process and tells you what’s happening:
- Digestion (0–4h) — Working through your last meal
- Stabilizing (4–8h) — Blood sugar settling, energy stabilizing
- Fat Burning (8–12h) — Glycogen depleted, fat metabolism begins
- Ketosis (12–16h) — Ketone production underway
- Deep Ketosis (16h+) — Full ketosis, peak fat burning
Fasting schedules
Choose from presets or dial in exactly what works for you:
- 16:8 — 16 hours fasting, 8-hour eating window
- 12:12 — A gentler 50/50 split
- Custom — Any ratio from 1:23 to 23:1, set with a stepper
History and stats
Every completed fast is logged. The History tab shows your current streak, longest streak, total fasts completed, and total hours fasted, with your fasts grouped by week and a small stage bar for how far each one got. You can also export your full history as a CSV file.
Notifications
Optional reminders let you know:
- One hour before your fast is scheduled to end
- When you reach your goal
- Four hours after your goal, in case you forgot to end the fast
- One hour before your next fast is due to start
You can also set a preferred daily start time to keep your schedule consistent.
Share your fasts
When you finish a fast, FastingWindow makes a card you can share, sized for Instagram Stories. Swipe between two styles, Sunrise and Cream, and the app remembers the one you like. Each card shows how long you fasted, whether you hit your goal, how far through the stages you got, and your streak.
Home Screen and Lock Screen widgets
Small and medium Home Screen widgets show your current fast and stage, or a countdown to your next fast while your eating window is open. On the Lock Screen, pick a dial, a details widget with your stage and time left, a line next to the date, or any mix of them.
Made for iPad too
On iPad, FastingWindow uses the extra room: while you fast, every stage is listed with the time you’ll reach it, and between fasts you’ll see your week at a glance. History adds a two-week chart of your fasts against your goal.
No account, no cloud
All data stays on your device. There’s no account to create, no server, and no internet connection required.
Pricing
FastingWindow includes a 60-day free trial. After that, unlock forever for a one-time $2.99 payment. No subscription, no recurring charges.
If you need to restore a previous purchase on a new device, use the “Restore Purchases” button in Settings.
Support
Questions, feedback, or something not working right? Email us at support@moonlabs.app and we’ll get back to you.
Common questions
Can I log a fast I already started?
Yes. When you tap “Start Fast,” you can pick any start time up to 24 hours in the past.
Can I log a fast that already ended?
Yes. When you tap “End Fast,” you can pick any end time between when you started and now.
I bought the app on another device — how do I unlock it?
Go to Settings and tap “Restore Purchases.” As long as you’re signed in with the same Apple ID, it will unlock for free.
My notifications aren’t showing up.
Make sure notifications are enabled both inside FastingWindow (Settings → Reminders) and in your iPhone’s Settings app under FastingWindow → Notifications.
How do I export my history?
Open the History tab and tap the share icon in the top-right corner. This generates a CSV file you can save to Files, email to yourself, or open in any spreadsheet app.