Progress ring
A full-circle timer that shows your fast at a glance, with color shifting as stages advance.
Intermittent fasting, distilled
Fast with purpose,
not with guesswork.
A fasting timer that shows you exactly where you are. Progress ring, stage tracking, heat ramp, and plans built for how you actually eat.
- Free
- No ads
- Private by default
- Works offline
16:8Most popular plan
7Metabolic phases tracked
0Ads, ever
100%On-device, offline-first
The timer
A ring that glows
hotter as you fast.
Every fast has a shape. Temper maps yours onto a progress ring that changes color as you move through metabolic phases, from the cool blue of early digestion, through teal and green as fat burning kicks in, into the gold of ketosis and the ember of autophagy and recovery. The heat ramp is not decorative. It tells you where you actually are.
Progress ring
A full-circle timer that fills and changes color as your fast deepens. Current stage always visible at a glance.
Metabolic phases
Seven phases from fed and sugar settling through fat burning, ketosis, autophagy and recovery, each marked with a time threshold and a short description.
Heat ramp
Cool blue at the start, warming through teal and green, settling into gold and ember as your fast matures. Visual rhythm you can feel.
Ring styles
Classic, heat, minimal, segments, gradient, and dots. Pick the style that fits how you prefer to see time pass.
Built for rhythm
Everything your fasting routine needs.
Fasting plans
Your protocol,
ready to go.
16:8, 18:6, OMAD and more come built in for free. Go Pro for 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.
History and stats
A record of
every fast.
Past sessions, completion rates, current streak, and longest streak are all tracked automatically. No manual logging, just start and stop.
Trends and insights
See the shape
of your weeks.
Streaks, completion rates and a 14-day trend build up as you fast, no manual logging. Pro adds smart insights and a weekly rhythm view, so the patterns that actually stick become obvious.
Pro upgrade
Free logs it.
Pro reads it.
The full timer, phases, streaks, trends and history stay free. Pro adds smart insights, a weight curve matched to your fasts, streak protection, a home screen widget, custom accent colors and data export. Available monthly, yearly, or as a one-time lifetime unlock.
Fasting buddy
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. No email, no password, and you can delete it anytime.
The idea
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 in your eating window or not? Temper answers that question with a single glance at the ring. No calorie counting, no food logging, just a timer you can trust.
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.
Fasting stages
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.
Fed (0h)
Your fast has just begun and your body is still processing your last meal. Insulin is elevated and your body runs on the energy from what you ate.
Tap or click any stage to explore it. Keyboard: Tab to focus, arrow keys to navigate.
The full picture
Everything a faster needs.
Fasting plans
16:8, 18:6, OMAD and more, free. Go Pro for custom windows, long protocols, and a different plan per weekday.
Metabolic phases
Seven phases from fed through deep recovery, each shown clearly on the ring as time passes.
Plan rotation
Assign a different fasting plan to each day of the week. Set it once, Temper handles the rest.
Streak tracking
Current streak and longest streak tracked automatically. No manual input needed.
Reminders
Local notifications for fast completion, eating window ending, and stage milestones. All on-device.
Fasting buddy
Pair up over a private code, share your streak and plan, and keep each other on track. Opt-in, no account.
Weight and insights
With Pro, log your weight and see it tracked against your fasting streaks, plus smart insights on your patterns.
Privacy-first
No ads, no trackers, no analytics. Your fasting log stays on your device; the optional buddy syncs only what you share.
No ads, ever
Completely ad-free. No banners, no interstitials, no sponsored content of any kind.
Good to know
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) for free. Pro unlocks 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 ring to start your fast. The progress ring fills over time and changes color as you move through metabolic phases, from the cool blue of early digestion through green fat burning to the gold of ketosis and the ember 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 is a timing tool, not a nutrition or diet app. It tracks when you fast, not what you eat. For any questions about nutrition or how fasting fits your health situation, consult a qualified healthcare provider.
Is Temper free?
Yes. The core fasting timer, phase tracking, history, streaks, trends, and reminders are all free. Pro is optional and adds smart insights, a weight curve, streak protection, a weekly rhythm, a home screen widget, custom accent colors and export. It is available monthly, yearly, or as a one-time lifetime unlock. There are no ads either way.
Does Temper collect any data?
Your fasting sessions, plans, and stats are stored locally on your device, with no ads, no analytics and no tracking. 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.
Ready to fast with clarity?
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