Fasting timer with a moon that fills as you fast.
Questions, bug reports, feature ideas — we read everything.
Email SupportWe usually reply within 2 business days. To help us help you faster, please include your device model, iOS version, and the app version (found at the bottom of the app's settings screen).
How does the moon work?
The moon is your fast made visible. It starts as a dark new moon and fills gradually as your fasting window elapses. When your fast completes, the moon is full. The time it takes is set by the fasting duration you choose, or by the plan MoonFast generated for you.
What is the difference between the free version and Pro?
The free version is a complete fasting timer with the moon, unlimited fasts and full history. MoonFast Pro adds planning: a personalized week-by-week schedule that progresses gradually, rest days arranged for you, and reminder notifications so you don't miss the moment your moon fills.
How do I cancel my subscription?
Subscriptions are managed by Apple, not by the app. Open your device Settings → Apple Account → Subscriptions, select MoonFast, and tap Cancel Subscription. You can also manage it at apps.apple.com/account/subscriptions. Cancelling stops future renewals and you keep Pro until the current period ends.
I paid but Pro isn't unlocked. What do I do?
Open the app, go to the Pro screen and tap "Restore Purchases". Make sure you are signed in with the same Apple Account you used to buy. If it still doesn't unlock, email us with your purchase receipt and we will sort it out.
Are my fasting records backed up?
Your records are stored only on your device, which is why the app works fully offline and collects nothing. This also means we cannot restore them for you: if you delete the app or reset your device, the records are gone. Device backups made through iCloud or your computer will include the app's data.
Can I change when my fast starts after the fact?
Your plan is anchored to the time you normally finish your last meal. You can adjust your answers at any time from the plan review screen, and MoonFast will regenerate the schedule from that point forward.
Is fasting safe for me?
MoonFast is a timing tool, not medical advice. Fasting is not appropriate for everyone — including people who are pregnant or breastfeeding, people with diabetes, and people taking medication. Talk to a healthcare professional before changing how you eat.
Which languages are supported?
The app interface is available in English and Simplified Chinese. More languages are on the way.