Comparison

Just Fast vs Fasting Timer by TrainerDay

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Just Fast

This app tracks both your fasting periods and your eating windows, offering a unique dual-countdown feature. It visualizes metabolic phases like fat burning and ketosis, supports various fasting methods, and provides insights into your progress. It's designed to be user-friendly and privacy-conscious, working entirely offline.

Highlights
  • Eating window countdown
  • Fasting phases visualization
  • Support for multiple fasting methods
  • Streak tracking with grace periods
  • Pattern insights
  • Weight and BMI tracking
  • Smart notifications
  • 100% offline functionality
Features
Read full description

Just Fast is the intermittent fasting timer that tracks both your fast and your eating window — a combination no other fasting app offers. Whether you're new to 16:8 or pushing into 20:4, OMAD, or custom schedules, Just Fast gives you a clear, distraction-free timer alongside the insights to understand what your body is doing and build habits that stick. EATING WINDOW COUNTDOWN — ONLY IN JUST FAST Most fasting apps tell you when your fast ends. Just Fast also tells you when your eating window closes. Know exactly how much time you have left to eat, so you stop overrunning your window by accident. KEY FEATURES • Eating Window Countdown — track when your eating window closes, not just when your fast ends • Fasting Phases — see fat burning, ketosis, and autophagy stages visualized in real time • All Major Fasting Methods — 16:8, 18:6, 20:4, OMAD, 14:10, 12:12, 24h, and custom durations • Streak Tracking with Grace Periods — maintain your momentum even on tough days • Pattern Insights — review your fasting history and discover your most consistent windows • Weight Tracking with BMI — log weight entries and track progress over time • Smart Notifications — reminders that support your schedule, not disrupt it • Beginner-Friendly Onboarding — choose your goal, fasting expertise, and preferred schedule in minutes • 100% Offline — no account, no signup, no cloud required • 15 Languages — English, German, French, Spanish, Polish, Portuguese, Italian, Japanese, Korean, Arabic, Russian, Swedish, Finnish, Norwegian, Turkish UNDERSTAND YOUR FAST, NOT JUST YOUR TIMER Just Fast visualizes the metabolic phases of fasting as they happen: fat burning begins around hour 12, ketosis deepens past hour 18, autophagy activates beyond hour 24. You do not need a biology degree — the app shows you where you are and what your body is doing. FREE AND LIGHTWEIGHT All core features are free. No subscription. No paywall. Just Fast is also one of the lightest full-featured fasting apps available — under 50MB download, compared to 200MB+ for most competitors. Fast to download, fast to start. Note: The app is free with light banner ads on secondary screens (history, settings). The main fasting timer screen is completely ad-free. PERFECT FOR • Beginners starting their first 16:8 protocol • Intermediate fasters exploring 18:6, 20:4, or OMAD • Anyone who wants fasting phases explained without complexity • People managing multiple fasting schedules across 15 languages • Privacy-conscious users who prefer no-account apps Download Just Fast and start your first fast today — no signup required. --- Privacy Policy: https://justfast.app/privacy Support: support@justfast.app

About

Fasting Timer by TrainerDay

This app simplifies intermittent fasting with a one-tap start and customizable durations. Track your progress visually and review your fasting history. It's designed for easy habit building without complex features.

Highlights
  • One-tap fast start
  • Customizable fasting durations
  • Flexible start times
  • Visual progress tracking
  • Fasting history
  • Shareable results
Features
Read full description

Fasting Timer is a simple, no-fuss intermittent fasting tracker designed to help you build healthy fasting habits. It's the ultimate app for ADF fasters. Each day when you start your fast. It's just one click, even when you forget to start it at your normal fasting time. Features: • One-tap start - Begin your fast instantly • Customizable durations - Set your preferred fasting window (12, 14, 16, 18, 20+ hours) • Flexible start times - Start now or schedule for later • Visual progress - See your fasting progress at a glance • History tracking - Review your completed fasts • Share your achievements - Export and share your fasting results Whether you're doing 16:8, 18:6, or any other intermittent fasting schedule, this app makes it easy to track your fasting windows without complicated setup or unnecessary features. Free and simple. Start fasting today.

Screenshots

Just Fast4 screens
Fasting Timer by TrainerDay4 screens

Verdict

The call

The clearest difference is ads: Fasting Timer by TrainerDay at none against Just Fast's shown. Fasting Timer by TrainerDay also leads on monetization model (free vs ad-supported). On price, rating, review sentiment and ratings volume there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 5.0 for Just Fast against 5.0 for Fasting Timer by TrainerDay. Both are backed by a comparable volume of ratings — 7 and 12 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

Scorecard2 real differences · 8 level
Just Fast versus Fasting Timer by TrainerDay: the parameters behind the verdict, then further details
ParameterJust FastFasting Timer by TrainerDay
PriceFreeFree
Rating5.0 (7 ratings)5.0 (12 ratings)
Positive reviews100.0% of reviews100.0% of reviews
Number of ratings712 — better
Update frequencyEvery 3 weeks—
AdsYesNo — better
In-app purchasesNoNo
MonetizationAd-supportedFree — better
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS14.0 — better15.1
Further details — not scored
Size47 MB30 MB
Age rating17+17+
DeveloperAdrian CabalaTrainerDay Inc

Customer experience

Just Fast

All ratings7 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Fasting Timer by TrainerDay

All ratings12 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Just Fast

No in-app purchases

None

Fasting Timer by TrainerDay

No in-app purchases

Questions

Is Just Fast free?
Just Fast is free to download, with no in-app purchases.
Is Fasting Timer by TrainerDay free?
Fasting Timer by TrainerDay is free to download, with no in-app purchases.
Which has better reviews, Just Fast or Fasting Timer by TrainerDay?
Just Fast and Fasting Timer by TrainerDay are both rated 5.0 out of 5 on the App Store, from 7 and 12 ratings respectively.
Do Just Fast or Fasting Timer by TrainerDay have ads?
Just Fast shows ads; Fasting Timer by TrainerDay does not.

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