Seven zones between
your last meal and your next.
A fasting timer that shows you exactly where you are. Depth gauge, stage tracking, zone colors, and plans built for how you actually eat.
- Free
- No ads
- Private by default
- Works offline
A gauge that sinks
deeper as you fast.
Every fast has a shape. Temper reads yours on a depth gauge, and each metabolic phase is a zone you descend through: dusk gold while your last meal is still working, shallow blue as sugar settles, deep blue as reserves drop, green when fat burning takes over, lumen cyan at ketosis, violet at autophagy, and abyssal magenta past 24 hours. The zone ramp is a readout. It tells you where you actually are.
Depth gauge
One circular instrument. A thread of light descends the scale, your current zone glows, the ones ahead only shimmer.
Metabolic phases
Seven zones from fed and sugar settling through fat burning, ketosis, autophagy and recovery, each with its own light, a time threshold and an honest description of what is known.
Zone ramp
Dusk gold at the surface, sinking through blue and green into cyan, violet and magenta. The color is the hour.
Water that moves
The background is a night ocean with drifting marine snow, and it sinks with you: the longer the fast, the deeper the water gets.
Plans, records, patterns,
and a partner.
Your protocol,
ready to go.
16:8, 18:6, OMAD and more come built in, alongside long protocols, your own custom windows, and a weekly rhythm that sets a different plan for each weekday, so Monday's 16:8 and Sunday's OMAD are set once and just work.
A record of
every fast.
Past sessions, completion rates, current streak and longest streak are all kept for you. You start the fast and you end it, and the record writes itself.
See the shape
of your weeks.
Streaks, completion rates and a 14-day trend build up as you fast. Smart insights read your own record and a weekly rhythm view shows the patterns that hold.
Everything included.
For everyone.
Timer, phases, streaks, trends and history, plus smart insights, a weight curve matched to your fasts, streak protection, a home screen widget, ocean moods and data export. Temper is completely free. No purchases, no subscription, no ads.
Fast better
together.
Pair up with a friend over a private code and keep each other on track. Share your streak and plan, send a nudge, and chat, all opt-in. A code is the whole setup, and you can delete it anytime.
Why intermittent fasting?
Intermittent fasting is a pattern of eating where you cycle between periods of eating and not eating. Most approaches simply narrow the window during which you eat, without restricting what you eat. It is practiced for a range of personal reasons, and Temper does not make any health claims about it.
Simple by design
The whole protocol reduces to one question: are you inside your eating window? Temper answers it with a single glance at the gauge, and leaves your plate entirely to you.
Private by default
Your fasting log stays on your device. No ads, no trackers, no analytics. The one exception is the optional fasting buddy, which uses a server only when you switch it on and can be deleted anytime. What you do with your body is your business.
Where are you in your fast?
Temper tracks seven distinct phases. Tap any point on the timeline to learn what your body is doing at that phase.
Tap or click any stage to explore it. Keyboard: Tab to focus, arrow keys to navigate.
Everything in Temper, line by line.
Timer and record
- Depth gauge
- The full timer, with all seven metabolic zones live from the first minute.
- Built-in plans
- 16:8, 18:6, 20:4, OMAD and a handful more, ready to start.
- History
- Every fast you finish, kept with its plan, its length and how it ended.
- Streaks
- Current and longest, counted from your record without any input.
- Trends
- Completion rate and a 14-day curve, drawn as the fasts come in.
- Milestones
- Marks for your first fast, your first 24 hours, and the streaks you pass.
- Reminders
- Local notifications when the fast is done, when the window closes, and at each zone you reach.
- Fasting buddy
- Pair over a private code, share your streak and plan, send a nudge. Opt-in, and yours to delete.
Depth and comfort
- Smart insights
- What your own record says about the lengths and the days that hold.
- Weight curve
- Your weight drawn against your fasts, so the two can be read together.
- Weekly rhythm
- A different plan for each weekday. Set Monday and Sunday once, they run themselves.
- Custom and long plans
- Your own windows, and protocols that run past 36 hours.
- Streak protection
- One missed day absorbed, so a single slip keeps the run alive.
- Home screen widget
- Time left, without opening the app.
- Ocean moods
- Pick the light the whole app runs on.
- Export
- Your entire log as CSV or JSON, whenever you want it.
Frequently asked questions
What is intermittent fasting?
Intermittent fasting is a pattern of eating where you cycle between defined periods of eating and not eating. Common approaches include 16:8 (16 hours fasting, 8 hours eating) and 18:6. It focuses on when you eat rather than what you eat. Temper tracks your fasting window and shows you which stage you are in, without making any health or medical claims about the practice.
Which fasting protocols does Temper support?
Temper includes built-in plans for 16:8, 18:6, and OMAD (one meal a day), long protocols, fully custom windows you set yourself, and a weekly rhythm that assigns a different plan to each day of the week.
How does the fasting timer work?
Tap the gauge to start your fast. The light thread descends over time and changes color as you move through metabolic zones, from dusk gold and shallow blue through green fat burning to the cyan of ketosis and the violet of autophagy. Tap again to end your fast. The session is logged automatically.
What are the metabolic phases Temper shows?
Temper tracks seven phases: Fed (0h, your body is processing your last meal), Sugar settling (around 4h, insulin falls), Reserves drop (around 8h, liver glycogen declines), Fat burning (around 12h, metabolism shifts to fat), Ketosis (around 16h, the liver forms ketones), Autophagy (around 18h, cellular cleanup intensifies), and Recovery and hormones (around 24h). The exact timing varies by person and is shown as a general guideline, not medical advice.
Does Temper tell me what to eat?
No. Temper tracks the hours you fast. What goes on your plate is your call, and for anything about nutrition or how fasting fits your health situation, ask a qualified healthcare provider.
Is Temper free?
Yes, completely. The fasting timer, phase tracking, history, streaks, trends, reminders, smart insights, weight curve, streak protection, weekly rhythm, home screen widget, ocean moods and export are all included for everyone. There is nothing to buy, no subscription, and no ads.
Does Temper collect any data?
Your fasting sessions, plans and stats are stored locally on your device and stay there. The only data that can leave your phone is the optional fasting buddy: if you turn it on, a small profile (a display name, your current streak and plan label, never your individual sessions) syncs so your buddy can see it, and you can delete it anytime. See the privacy policy for the full details.
Does it work offline?
Yes, completely. Temper works without any internet connection. The timer, stage tracking, history, and notifications all run entirely on your device.
Start your first fast tonight.
Free on Google Play, and everything above runs from the first minute.