Comparison

SOL vs Sundial

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

Head to head
About

SOL

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SOL (์†”) is Korean for pine tree. Like the pine that endures through every season, SOL stands with you through every fast. WHAT MAKES SOL DIFFERENT Most fasting apps just show a timer. SOL shows you what is happening inside your body as the hours pass, with the research behind it. As you fast, SOL guides you through eight phases: Fed State, Insulin Dropping, Fat Burning, Ketosis, Autophagy, Deep Autophagy, Growth Hormone Surge and Immune Reset. FEATURES โ€ข A calm timer with a progress ring and phase markers โ€ข Your fast on the lock screen and in the Dynamic Island โ€ข All 8 phases explained, with links to the published studies โ€ข A goal dial from 12 to 72 hours, or an open fast with no limit โ€ข Started earlier? Set the time you last ate, and correct it later โ€ข Switch the timer between time elapsed and time to go โ€ข A daily reminder to start your fast โ€ข Your Journey: stats, streaks, a 7 day view and your history โ€ข Edit, add or delete past fasts โ€ข Guidance on breaking your fast gently โ€ข Home screen widget โ€ข "Start my fast" with Siri โ€ข Share your results with a beautiful card โ€ข Light and dark mode with handcrafted watercolor textures FASTING TOGETHER If you like, join the live count of people fasting right now. It is optional, anonymous and off until you turn it on. YOUR DATA No account, no ads, no tracking. Your fasting data stays on your device unless you choose to join the community count or turn on iCloud backup. DESIGNED WITH INTENTION SOL is inspired by the simplicity of nature. No clutter and no paywall. Just you, your fast, and a clearer picture of what your body is doing. SOL is free. If you enjoy it, you can leave a tip. ABOUT THE SCIENCE Phase information is based on peer-reviewed research, with direct links to the sources. Some findings come from animal studies, and every body responds differently. SOL offers general wellness information and is not medical advice. Please talk to a doctor before fasting, especially for longer fasts. Begin your fast. Know your body. Grow like the pine.

About

Sundial

Features
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Finally, a fasting timer you buy once and own for life. No subscription. No account. No quiz-funnel paywall. Just open it and start your fast. Sundial is a calm, local-first tracker for intermittent fasting and OMAD (one meal a day). One quiet ring; a sun crosses the dial as your fast deepens. Warm paper-and-ember design, automatic dark mode. No neon, no confetti, no streak-shaming. It works fully offline from the very first tap. WHY SUNDIAL IS DIFFERENT - Pay once, $19.99. No $60-80/year renewals for a glorified timer. - No forced sign-up, no quiz funnel, no data siphoning. Cloud backup is optional, never required. - Fasting zones and stages are explained for free - learn what each stage is called, hour by hour. Most apps lock this away. - Custom durations up to 72 hours - log any fast you choose, with no upsell. - Retroactive editing: forgot to hit start or stop? Fix it, or log a past fast. - Your eating window anchors to when you actually broke the fast - not a rigid schedule. FREE FOREVER - Timer for every protocol: 16:8, 18:6, 20:4, OMAD, 36h, and custom. - Fasting zones and stage labels on the dial. - History, calendar, streaks, and weekly stats. - Weight, water, and mood logging. - Gentle notifications for start, end, and milestones. - Export everything to CSV or JSON in two taps. Your data is yours. LIFETIME UNLOCK ($19.99, ONCE) - Cloud backup and cross-device sync. - Insights: deeper trends over time. - The full Field Notes library of calm, readable articles - including a plain explainer of what autophagy is. Everything you need to fast is already free. Lifetime is for going further, on your terms. BUILT TO RESPECT YOU Local-first and private by design. No ads, no data mining, no guilt loops, no upsell screens between you and your timer. A quieter way to keep time. Sundial tracks time. It is not medical advice. Talk to a healthcare professional before changing how you eat or starting extended fasts, especially if you are under 18, pregnant, managing diabetes, or have a history of disordered eating.

Screenshots

SOL4 screens
Sundial4 screens

Verdict

The call

SOL and Sundial are too close to call on the numbers: across 5 compared parameters โ€” price, ads, in-app purchases and device support among them โ€” neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

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

CostPrice ยท In-app purchases ยท Ads ยท Monetization

Both are free to download. SOL sells 3 one-off in-app purchases and Sundial sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

ScorecardNo meaningful differences
SOL versus Sundial: the parameters behind the verdict, then further details
ParameterSOLSundial
PriceFreeFree
Update frequencyFortnightlyโ€”
AdsNoNo
In-app purchasesYesYes
DevicesiPhone, iPod โ€” betteriPhone
Requires iOS16 โ€” better16.4
Further details โ€” not scored
Size7 MB65 MB
Age rating4+4+
DeveloperDanny LinsnerVitalii Iudin

In-app purchases

3 purchases

SOL

One-time3
  • Seedling Tip$1.99
  • Sapling Tip$3.99
  • Pine Tip$8.99
1 purchases

Sundial

One-time1
  • Sundial Lifetime$19.99

Questions

Is SOL free?
SOL is free to download, with in-app purchases available.
Is Sundial free?
Sundial is free to download, with in-app purchases available.
Do SOL or Sundial have ads?
Neither SOL nor Sundial shows ads.

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