Comparison

Happy Scale vs Zero

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

Head to head
About

Happy Scale

This app helps you understand your weight loss journey by analyzing scale fluctuations. It smooths out daily variations to reveal your true progress, predict future weights, and break down goals into manageable milestones.

Highlights
  • See true progress with mathematical analysis
  • Smooth out weigh-in fluctuations
  • Predict future weight
  • Break down goals into milestones
  • Integrates with Apple Health
  • BMI calculator
Features
Read full description

Dieting is hard enough. But when you work hard, hop on the scale, and see a number that’s higher than yesterday? Well, that’s just not fair! It’s time to tame the scale! Happy Scale helps you make sense of the frustrating ups and downs of weigh-ins by using mathematical analysis to make sense of your scale weights. You’ll: • understand your true trend, • take the sting out of plateaus, and • be able to predict what you’ll weigh for an upcoming event • SEE YOUR TRUE PROGRESS: Happy Scale uses sophisticated math to learn the true trend of your progress. You can see what you’re really losing each week. • NO MORE PLATEAUS: Use the moving average progress tracking options to see steady progress every day! • SLOW AND STEADY WINS THE RACE: Have a lot to lose? Break your weight loss goal into small, incremental milestone goals so you can focus on short-term, achievable goals! • THE PERFECT SUPPLEMENT: Use this app in conjunction with other popular apps. Weight entries can be automatically imported from apps that support exporting to the Apple Health app, and Happy Scale will export all your weights to Apple Health so other apps can see them. • IMAGINE YOUR SUCCESS: See predictions about what you’ll weigh in the future if you keep up your current trends, and set commitment goals for yourself! • KNOW YOUR NUMBERS: Our new BMI calculator shows you exactly where you stand and what weight ranges you need to hit for different health categories. No more guessing if you’re almost there! • WORKS ON ALL YOUR DEVICES: Seamlessly sync between your iPhone and iPad! So, have your previous diets failed because you lost motivation? Try Happy Scale today and join thousands of users who use this app to TAME THE SCALE! ------------------ This app optionally integrates with Apple Health. It is an opt-in feature that’s accessible from the Settings menu. ------------------ If you purchase a monthly or yearly subscription, payment will be charged to your iTunes account. Your account will automatically be charged for renewal within 24-hours prior to the end of the current subscription unless you disable auto-renew. You can turn off auto-renewal at any time by going to your Account Settings on the App Store after purchase. Privacy Policy: https://happyscale.com/privacy Terms of Use: https://happyscale.com/terms

About

Zero

This app tracks intermittent fasting and nutrition to help users achieve real body composition changes. It integrates fasting, protein intake, meals, hydration, and habits for a holistic approach to weight loss and metabolic health.

Highlights
  • Intermittent fasting timers and streaks
  • Smart meal logging with photo recognition
  • Personalized daily protein target tracking
  • Integrated fasting and protein tracking
  • Water and habit tracking
  • Science-based insights on fasting and nutrition
Features
Read full description

Zero is the all-in-one fasting tracker and nutrition app built for real results. Most fasting and weight loss apps stop at simply tracking fasts or calories. Zero connects the full picture — fasting, protein, meals, hydration, and habits — so you actually change your body composition, not just your eating schedule. Here’s how Zero helps you get there: • Track your intermittent fasting — Engage timers, streaks, and insights keep you stay motivated and consistent across your entire fasting journey. • Log meals the smart way — Skip the tedious manual meal entry routine. With Zero Plus, snap a photo and get instant macros, protein composition, and clarity on how effectively your meals support your goals. Your first meal logs are on us, so you can try it before you subscribe. • Hit your Protein Score — Zero Plus tracks a personalized daily protein target that adapts to your weight and goals. Better protein = better satiety, better muscle retention, better weight loss. Zero makes it automatic. • Complete the equation: Fasting + Protein — Most people fast or track meals. Zero brings them together so you lose weight, protect muscle, and avoid the pressure and guilt of traditional calorie trackers. • Stay hydrated to power your fasts — Water tracking with Zero Plus helps you maintain energy, reduce cravings, and support metabolic function throughout the day. • Build healthy habits that actually matter — Track movement, sleep, mood, and other daily pillars that reinforce your fasting and fueling routine. • Challenge yourself — Hit protein targets, maintain fasting streaks, and stay accountable with motivating challenges built around outcomes, not vanity metrics. • Learn the real science — Understand how fasting, protein, and hydration work together for sustainable weight loss and metabolic health — with insights from leading experts. • See measurable progress — Watch your streaks grow, your protein consistency rise, and your body composition improve with clean, insightful trend views. Whether you’re starting out or optimizing an existing routine, Zero gives you the structure, guidance, and clarity most apps miss. Zero is not a medical device and does not provide medical advice, diagnosis, or treatment. Always consult your doctor or qualified healthcare provider before making any changes to your diet, fasting routine, or health regimen. Zero is free to download, with fasting timers, streaks, weekly trends, expert articles, and challenges included. Zero Plus is an optional subscription that unlocks photo meal logging and your Protein Score, water tracking, custom fasts and saved presets, Fat-Burning Mode, the mood journal and daily habit insights, premium articles and Plus-only challenges, and monthly, yearly, and correlated charts. A free trial is available. Payment for Zero Plus will be charged to your Apple Account when you subscribe. Subscriptions automatically renew unless auto-renew is turned off at least 24 hours before the end of the current period. Manage your subscription in your Account Settings. Read more terms & conditions: Terms of use: https://www.zerolongevity.com/terms-of-use Privacy policy: https://www.zerolongevity.com/privacy-policy

Screenshots

Happy Scale4 screens
Zero4 screens

Verdict

The call

Happy Scale and Zero both sit at 4.9 stars, but that hides the real split: 92% of Happy Scale's written reviews are positive against 32% of Zero's. Happy Scale also leads on update cadence (every 5 days vs every 2 weeks). Zero's advantage is monetization model (freemium vs subscription) and ratings volume (445K vs 58K). On price, rating, ads and in-app purchases 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. Happy Scale sells 8 in-app purchases, starting at $1.99 per month and Zero sells 10 in-app purchases, starting at $9.99 per month. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.9 for Happy Scale against 4.8 for Zero. That said, the two scores are not equally well evidenced: Zero has 445K ratings behind it against 58K, so its average is the more settled of the two. Written reviews are what separate them: 92% of Happy Scale's written reviews are positive against 32% of Zero's.

UpkeepUpdate frequency

Happy Scale ships an update every 5 days, Zero every 2 weeks. Both last shipped on November 1, 2026.

Scorecard4 real differences · 7 level
Happy Scale versus Zero: the parameters behind the verdict, then further details
ParameterHappy ScaleZero
PriceFreeFree
Rating4.9 (58K ratings) — better4.8 (445K ratings)
Positive reviews91.6% of reviews — better32.2% of reviews
Number of ratings58K445K — better
Update frequencyEvery 5 days — betterEvery 2 weeks
AdsNoNo
In-app purchasesYesYes
MonetizationSubscriptionFreemium — better
Best chart rank#178#135 — better
DevicesiPhone, iPadiPhone, Apple Watch
Requires iOS16.0 — better17.0
Further details — not scored
Size66 MB195 MB
Age rating12+17+
DeveloperFront Pocket Software LLCZero Longevity Science, Inc.

Customer experience

Happy Scale

All ratings58,108 ratings
Positive98.2%
Neutral1.2%
Negative0.6%
Written reviews729 reviews
Positive91.6%
Neutral1.6%
Negative6.7%

Zero

All ratings445,285 ratings
Positive96.3%
Neutral2.1%
Negative1.6%
Written reviews1,393 reviews
Positive32.2%
Neutral8.5%
Negative59.3%

User reviews

Happy Scale

From 58K App Store ratings

What we love

  • 👍 Excellent weight loss support tool
  • 👍 Motivating and engaging to track weight
  • 👍 Provides great insights and predictions
  • 👍 Smooths out weight fluctuations
  • 👍 Breaks down weight loss journey into milestones

Room to improve

  • 🐛 Reminders don't work for some users
  • 💰 Subscription model is expensive for some

Zero

From 445K App Store ratings

What we love

  • 🚀 Easy to use
  • 📊 Helpful tracking and data
  • 💡 Informative learning resources
  • 🔍 Detailed fasting information
  • 🤝 Sense of community

Room to improve

  • 💰 Expensive premium subscription
  • 🔒 Forced account creation
  • 🙄 Intrusive ads and upsells
  • 🤔 Inconsistent or confusing UI changes
  • 🐛 Syncing and login issues

Bugs and requests

Happy Scale

Reported bugs

1 issue
  • Reminders don't work for some users

Requested features

4 requests
  • Add ability to track body measurements and body fat percentage
  • Provide more chart/graph options (60-day, 6-month)
  • Add a watch app or complication for easier access
  • Implement more celebratory features when reaching goals

Zero

Reported bugs

3 issues
  • Password reset problems
  • Inaccurate fasting time tracking
  • Inability to exit trial without subscribing

Requested features

6 requests
  • Custom fasting periods longer than 24 hours
  • Ability to edit fasting type and duration
  • Integration with more health/fitness apps
  • Water intake tracking
  • Personalized fasting recommendations
Show 1 more
  • Improved data visualization and analytics

In-app purchases

8 purchases

Happy Scale

Subscriptions2
  • Happy Scale Deluxe (Monthly)7 Days trial$1.991 Month
  • Happy Scale Deluxe (Yearly)7 Days trial$11.991 Year
One-time6
  • Tip $1$0.99
  • Tip $3$2.99
  • Tip $5$4.99
Show 3 more
  • Tip $10$9.99
  • Happy Scale Premium (Lifetime)$39.99
  • Happy Scale Deluxe (Lifetime)$39.99
10 purchases

Zero

Subscriptions10
  • Zero Plus Subscription2 variants$9.991 Month
  • Zero Plus Subscription7 Days trial$9.991 Month
  • Zero Plus Subscription$39.991 Year
Show 7 more
  • Zero Plus Subscription7 Days trial$49.991 Year
  • Zero Plus Subscription7 Days trial3 variants$69.991 Year
  • Zero Plus Subscription$69.991 Year
  • Zero Plus Subscription1 Year trial3 variants$69.991 Year
  • Zero Plus Subscription1 Month trial$69.991 Year
  • Zero Plus Subscription1 Month trial$89.991 Year
  • Zero Plus Subscription7 Days trial$89.991 Year

Questions

Is Happy Scale free?
Happy Scale is free to download, with in-app purchases available.
Is Zero free?
Zero is free to download, with in-app purchases available.
Which has better reviews, Happy Scale or Zero?
Happy Scale is rated higher. Happy Scale averages 4.9 out of 5 from 58K ratings, while Zero averages 4.8 from 445K ratings.
Do Happy Scale or Zero have ads?
Neither Happy Scale nor Zero shows ads.
Which is updated more often, Happy Scale or Zero?
Happy Scale ships an update every 5 days, and Zero every 2 weeks. Most recently, Happy Scale was updated on November 1, 2026 and Zero on November 1, 2026.
Which is more popular, Happy Scale or Zero?
Happy Scale currently peaks at #178 in the App Store charts, and Zero at #135. Chart position reflects recent download velocity rather than total install base.

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