Fasty

Fasty for iPhone and Apple Watch

A simple way to track your fast.

Start your timer. Follow your fast from your Lock Screen or wrist. See your routine take shape over time.

Download on the App Store

★ 4.9 · 94,000+ ratings worldwide

Fasty's active fasting timer with elapsed time, goal progress, start time and goal controls.
Fasty Live Activity on the iPhone Lock Screen with the active fasting timer, goal progress and End Fast control.

In Fasty. On your Lock Screen.

No account. No ads. Your own routine.

Flexible goals and easy corrections

Fit fasting around your day.

Choose a goal that fits your routine. Change it when plans change. If you forget to start or stop the timer, edit the times or add your fast afterwards.1

Fasty's goal picker with standard durations, custom hours and days, and an end-time option.
Choose a goal that works for you.
A recorded fast with editable start and end times and a Save button.
Forgot a tap? Correct the times.
  • Pick a standard goal or enter your own hours, days or end time.
  • Save the durations you use most as presets.
  • Edit start and end times, or add a fast you forgot to record.

“i like that you can edit the start time since i often forget to start the timer.”

kcwcc
Canada ·
App Store reviews · excerpt

Live Activities, widgets and Apple Watch

Your fast, at a glance.

See how long you’ve been fasting without opening Fasty. Follow your progress on the Lock Screen, check a Home Screen widget, or look at your wrist.2

Fasty Live Activity on the iPhone Lock Screen with the active fasting timer, goal progress and End Fast control.
Live progress on your Lock Screen.
Fasty on Apple Watch with the active timer, start and goal times, and End Fast button.
A quick check from your wrist.
Fasty's large widget on an iPhone Home Screen, showing an active timer and fasting zones.
Your timer, on your Home Screen.
  • Follow an active fast on your Lock Screen and in the Dynamic Island.
  • Keep your timer on the Home Screen with a widget.
  • Check, start and finish a fast from your Apple Watch.

“Love the live activity on the lock screen, beautiful simple app interface.”

andrejz2438
United Kingdom ·
App Store reviews · excerpt

Fasting zones

Follow your progress, one zone at a time.

See your current fasting zone, learn what it means and find out what comes next.3

Fasty's Fasting Zones screen with explanations and progress through the current zone.
Learn about each fasting zone.
  • Follow your progress through the fasting zones.
  • Read an explanation of each fasting zone.
  • Choose whether to show fasting-zone icons on your timer.

Exercise-adjusted fasting zones · Pro

Your workouts count, too.

Give your workouts credit. Fasty uses workout calories and resting energy from Apple Health to bring later fasting zones forward in your progress.4

Fasty's adjusted fasting time panel, showing fasting and workout contributions side by side and progress through the current fasting zone.
See the contribution from your workout.
  • Give your workout a visible contribution to your progress.
  • See fasting time and the activity adjustment side by side.

Totals, streaks and milestones

See how far you've come.

Every recorded fast adds up. See your total fasting time, completed fasts and milestones. Follow your current streak and look back at your best.5

Fasty's statistics summary with total fasting time, fast count, current and maximum streaks, and earned badges.
Your time, streaks and milestones add up.
Fasty's green timer after reaching its 16-hour goal, with the fast still active.
Goal reached. Finish when you're ready.
  • See your total fasting time, fast count and longest recorded fast.
  • Follow your current streak and compare it with your best.
  • Choose how qualifying days or fasts count toward your streak.

Start your next fast.

Choose your fasting goal, start the timer and follow your progress.

Download on the App Store

Timeline, calendar and statistics

Understand your fasting routine.

Revisit your fasts in a calendar, or see fasting and eating windows together on a timeline. Compare weeks and months to understand how your routine changes over time.6

Fasty's populated September calendar with a selected day and its recorded 18-hour fast.
Choose a day. Revisit your fast.
Fasty's continuous fasting and eating-window timeline with one 30-day streak heading.
A month of fasts. A habit taking shape.
  • See fasts, eating-window gaps and streaks in one timeline.
  • Select a calendar day to look at its recorded fasts.
  • Compare fasting and eating-window time across weeks, months and years.

Optional weight tracking

Your fasts and weight, in one place.

Log your weight and follow your progress in the charts. Keep your weight and fasting history together in one app.7

Fasty's month view with twelve demonstration weights gradually declining from 74.0 to 72.6 kilograms, a 73.3-kilogram average and fasting-time data.
See how your weight changes over time.
Fasty's dated demonstration weight records with small fluctuations, most recently 72.6 kilograms on October 14.
Dated weight records, kept together.
  • Log your weight, choose your units and set a weight goal.
  • See weight history, charts and estimated trends.
  • Optionally sync weight entries with Apple Health.

“I also like that it also has a simple weight log to easily keep track in one place without having to download another app.”

autshi
United States ·
App Store reviews · excerpt

Reminders and notifications

Don't forget your fast.

Get a reminder to start fasting and record your fast. Know when you reach your goal, enter a new fasting zone or finish your eating window.

Fasty's Fast Reminders settings with a daily 20:00 reminder enabled and an explanation that it only notifies you when you are not fasting.
A daily reminder at your chosen time.
A real delivered Fasty notification on the iPhone Lock Screen saying Start your fast.
Know when to start fasting.
  • Set daily reminders to start fasting.
  • Get notified when you reach your fasting goal.
  • Choose alerts for fasting zones and your eating window.

Siri and Shortcuts

A shortcut to your fast.

Check and control your fast with Siri, Shortcuts and interactive snippets, without opening Fasty. Build automations around your routine.8

A shortcut in Apple's Shortcuts app using Fasty's Get current fasting state action.
Run an action from Shortcuts.
A real Fasty current-state result snippet shown over the Shortcuts editor, with fasting progress and controls.
See and control your fast without opening Fasty.
  • Start or finish a fast and check your fasting state with Siri or Shortcuts.
  • See your progress and control your fast in interactive snippets, without switching apps.
  • Change your start time or set an exact goal end time without opening Fasty.
  • Find, filter and sort recorded fasts, then use the results in other shortcuts.

Themes and personal preferences

Make Fasty feel like yours.

Choose a theme or create your own colours. Set how your timer counts, pick the statistics you see and decide what counts toward your streak.9

Fasty's active fasting timer using the predefined Ocean theme, with a blue progress ring and background.
Ocean: another look for your timer.
  • Choose a theme or customize your colours and gradients.
  • Show elapsed time or time remaining, with optional seconds.
  • Choose which cards appear in Statistics.
  • Count qualifying days or completed fasts toward your streak.

From people who use Fasty

Simple to use. More when you need it.

“Simple, clean, and then can be very in-depth if you chose.”

Dilrod7
United States ·
App Store reviews · excerpt

“Great app. Love the widgets. It's simple and does the job well.”

Lina~~~~
Australia ·
App Store reviews

“Love the ease of use, and how you can change your goal during fast.”

Paula Yvette
United States ·
App Store reviews

“I love that I can use the widgets to quickly start and stop my fasts”

cosmic.tot
United States ·
App Store reviews · excerpt

“Good overview to track the week.”

Mammy of 2
United Kingdom ·
App Store reviews · excerpt

“Editing my start/end times, viewing my fasting history in the statistics section, and tracking my weight via Apple Health are my favorites.”

Mr Candor
United States ·
App Store reviews · excerpt

Fasty Pro

More motivation. More control.

Give your workouts credit, build your routine and make Fasty your own. Follow and control your fast from your Home Screen, Lock Screen and wrist.4

Download on the App Store

Explore Pro and choose your upgrade in Fasty.

Give your workouts credit

See your workouts move your fasting-zone progress forward, with the exercise contribution shown beside your actual fasting time.

Build a habit that fits you

Save your usual fasting goals as presets. Choose how Fasty counts your streak so it reflects the routine you want to build.

Make it yours

Choose themes, customize colours and gradients, and pick the statistics that matter to you.

Control your fast everywhere

Start and finish from widgets and Live Activities. Edit your start time and goal through Shortcuts without opening Fasty.

Fasty's exercise-adjusted fasting-zone progress with fasting and workout contributions shown side by side.
Give your workouts credit.
Fasty's active timer using the Ocean colour theme.
Your colours. Your Fasty.
Fasty's estimated fasting-zone icons and active timer on Apple Watch.
Fasting zones on your wrist.
Fasty's large active widget with the current fasting zone, progress, remaining time and upcoming zones.
Your fasting zones, at a glance.
All Fasty Pro features

Workouts and weight

  • Exercise-adjusted fasting zones using Apple Health workouts
  • Apple Health weight sync

Widgets and Live Activities

  • Start and finish fasts from Home Screen widgets
  • Start and finish fasts from Live Activities
  • Full fasting-zone overview in large widgets
  • Your last completed fast in large widgets

Apple Watch

  • Edit the start time of an ongoing fast
  • Follow your fasting-zone progress
  • See your recent fasts in a chart

Your routine and appearance

  • Themes, custom colours and gradients
  • Choose which cards appear in Statistics
  • Customize how your streak is counted
  • Save your fasting goals as presets
  • Browse earlier months in your fasting calendar

Advanced Shortcuts and snippets

  • Change an ongoing fast's start time
  • Set an exact goal end time
  • Find, filter and sort recorded fasts for use in other shortcuts
  • Cancel a fast from a shortcut
  • Control your fast from interactive snippets

Help shape Fasty

  • Vote on Fasty's roadmap

Before you get started

A few useful answers.

Can I choose my own fasting goal?
Yes. Choose a standard goal, enter a custom duration or set an exact goal end time. You can change the goal during a fast. Save your own presets with Fasty Pro.
What if I forget to start or stop the timer?
Edit the start time of an active fast, add a missed fast, or correct a recorded fast's start and end times.
Does reaching the goal end my fast automatically?
No. The timer keeps counting after you reach the goal. End and save the fast when you're finished, or correct the end time if you forgot to stop it.
Does Fasty recommend a fasting routine?
Fasty tracks the routine you choose. It doesn't prescribe a fasting plan or provide personalized health advice.
How does Fasty know which fasting zone I'm in?
Fasty estimates fasting zones from time spent fasting. With workout adjustment enabled, it also uses workout and resting-energy data from Apple Health. These are estimates, not glucose or ketone measurements.
How does workout adjustment work?
Fasty Pro uses workout calories and resting energy from Apple Health to estimate the contribution of exercise to your fasting-zone progress. Your actual fasting time stays unchanged.
What can I use on Apple Watch?
Check your timer, choose a goal, and start or finish a fast from your wrist. Use complications and the Smart Stack for a quick look at your progress. Fasty Pro adds fasting-zone progress and a recent-fasts chart.
Can I track weight without Apple Health?
Yes. Log your weight manually, choose your units and follow your progress in Fasty. Optional Apple Health weight sync requires Fasty Pro and your permission.
Can I bring my records with me?
Export fasting and weight records as CSV. Fasty can import its compatible CSV files and completed fasts from supported Zero JSON exports. Imports don't transfer every setting or every field from another app.
What does Pro add, and can I restore a purchase?
Fasty Pro adds exercise-adjusted fasting zones, large widgets for fasting-zone progress and your last completed fast, Apple Health weight sync, themes, presets, customizable statistics and streak rules, interactive controls and extra Shortcuts and Watch features. It also lets you browse earlier months in the fasting calendar. Open Subscriptions & Purchases in Fasty's settings to restore or manage purchases and see current plans.

More questions? Visit Help · Contact me

Still getting better

Fasty 0.0.107 — your last fast in the widget

Completed-fast summaries in larger widgets, iPhone Duo support and larger-text improvements.

Read the update

I'm Kai Oelfke, the independent developer behind Fasty. Keep your fasting and weight records with CSV export, and follow the changelog to see what's new. Have a question? Contact me.

Ready to start?

Download on the App Store