WaterFast vs Onefast
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
WaterFast
This app provides a synchronized intermittent fasting timer designed for seamless use across your iPhone and Apple Watch. It offers detailed insights into fasting zones and hydration tracking, with a focus on privacy and a user-friendly experience.
- Synchronized iPhone and Apple Watch timer
- Fasting zone insights
- Hydration tracking
- Multiple fasting plans
- Streak calendar
- Data export
Read full descriptionHide full description
Some fasting apps charge many times more. WaterFast is a fraction of that — with a 3-day free trial on every plan. You decide. FASTING APPS HAVE A PROBLEM They're either overpriced, bloated with social feeds and AI coaching you never asked for — or they're simple but their Apple Watch app runs a separate countdown that drifts out of sync with your iPhone. Two timers for the same fast. Not optimal. WATERFAST IS DIFFERENT One timer. One source of truth. Your Watch doesn't follow your iPhone — it leads. Start, monitor and end your fast right from your wrist, even with your iPhone in your pocket. When you pick it up, everything matches. Always. To the second. TRY IT ALL FREE FOR 3 DAYS Start a 3-day free trial and unlock everything — no strings attached. Then keep it monthly, yearly, or one-time lifetime. Cancel anytime. EVERYTHING INCLUDED • Every plan: 16:8, 18:6, 20:4, OMAD, 5:2 and fully custom • Start & stop fasts from Apple Watch — it leads, iPhone follows • Live timer with progress ring and fasting zones • Streak calendar — don't break the chain, unlimited history • All Apple Watch complications (circular, corner, inline, rectangular) • Hydration tracking with one-tap logging and daily goal • Full stats: current streak, longest fast, total hours, success rate • Export your data as CSV • No account required BUILT FOR APPLE WATCH — REALLY Most fasting apps treat the Watch as an afterthought. WaterFast was designed wrist-first. The timer state lives in one shared place: start a fast on your Watch during dinner, check the zone on your iPhone the next morning — same fast, same seconds, zero drift. KNOW YOUR FASTING ZONES Track exactly what's happening in your body — from digestion through fat burning and ketosis to autophagy. Each zone explained in plain language, with science-based hour ranges. Educational reference only — not medical advice. HYDRATION, ON YOUR WRIST Log a glass of water with one tap on your Watch, with haptic confirmation, synced instantly to your iPhone and Apple Health. A PRICE THAT RESPECTS YOU WaterFast PRO: monthly, yearly, or one-time lifetime. Every plan starts with a 3-day free trial. We think a fasting timer shouldn't cost more than your streaming service. PRIVATE BY DESIGN No account. No ads. No tracking. Your fasting and hydration data never leaves your device (except to your own Apple Health, if you choose). Start your 3-day free trial and run your first fast in under a minute. --- Medical disclaimer: WaterFast provides educational information about fasting. It is not medical advice. Consult your healthcare provider before starting any fasting protocol, especially if you have a medical condition, are pregnant, or take medication. --- Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Onefast
Read full descriptionHide full description
A fasting timer that does one thing well. Pick a plan, tap Start, and Onefast counts. The time left is on your lock screen and in the Dynamic Island, so you never open the app just to look. When the goal is reached it tells you once, then keeps counting, up to seven days. ONE TAP No sign-up, no questions, no tour. The first screen is the plan picker with 16:8 already selected; the second is the timer. That is the whole setup. ALWAYS RIGHT The timer is a clock, not a counter. Force-quit the app, restart the phone, change time zone — it comes back showing the true elapsed time, to the second. The widget, the Live Activity and the app all read the same moment. YOURS TO EDIT Forgot to tap End? Fix the time afterwards. Add a fast you did last week. Overlaps are named in words, not blocked silently. Fasts longer than 24 hours are allowed — Onefast asks once whether you meant it, then never again. QUIET WHEN YOU WANT Three switches: Live Activity with Dynamic Island, the lock screen widget, and the home screen widget. Notifications turn on and off one kind at a time, and the mid-fast ones start off. PLANS 12:12, 14:10, 16:8, 18:6, 20:4 and one meal a day are built in. Up to five named custom plans and a weekly schedule with Pro. NO ADS. EVER. Not on the free tier, not after you buy. Onefast has no server, no account and no analytics. Your history lives on your iPhone and, if you turn it on, in your own private iCloud. ONEFAST PRO Unlimited history (free keeps the last 30 days), 30-day and all-time stats with charts, month and year summaries, insights from your own record, milestones you can share, a weekly schedule with rest days, up to five named custom plans, two-way weight sync with Apple Health, a weight goal line on your chart, ten ring colours and app icons or a colour of your own, a medium calendar widget, and CSV export. Two prices, one name: a yearly subscription that auto-renews until cancelled, or a single lifetime purchase. No trial. The price is on screen before you tap anything. Everything that makes the timer usable — lock screen, notifications, backup, editing — stays free with or without Pro. Onefast is a timer. It gives no medical or dietary advice; talk to a professional before changing how you eat. Available in English, 日本語, 한국어, 繁體中文, Italiano, Nederlands, Deutsch, Français, Español, Português (Brasil), العربية, Türkçe and Tiếng Việt. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://primetruthteam.github.io/onefast/privacy/
Screenshots
Verdict
The clearest difference is update cadence: Onefast at every 2 days against WaterFast's weekly. On price, ads, in-app purchases and device support 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
Both are free to download. WaterFast sells 3 in-app purchases, starting at $2.99 per month and Onefast sells 2 in-app purchases, starting at $9.99 per year. Whichever you choose, the download price is not the number that matters.
WaterFast ships an update weekly, Onefast every 2 days. The most recent releases landed on November 5, 2026 and October 31, 2026 respectively.
| Parameter | WaterFast | Onefast |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (2 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 2 — better | — |
| Update frequency | Weekly | Every 2 days — better |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Freemium | — |
| Devices | iPhone, Apple Watch — better | iPhone |
| Requires iOS | 17.0 | 17.0 |
| Further details — not scored | ||
| Size | 3 MB | 4 MB |
| Age rating | +4 | 4+ |
| Developer | LUIS ORLANDO LAZO GONZALEZ | Nguyen Dinh Chung |
In-app purchases
WaterFast
- WaterFast PRO Monthly3 Days trial$2.991 Month
- WaterFast PRO Yearly3 Days trial$9.991 Year
- WaterFast PRO Lifetime$24.99
Onefast
- Onefast Pro (Yearly)$9.991 Year
- Onefast Pro (Lifetime)$19.99









