Comparison

Fat Burned vs Bubbles

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

Head to head
About

Fat Burned

Features
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Ever wonder how much fat you actually burn in a day? FatBurn turns your Apple Health data into clear, actionable fat burn estimates — no guesswork, no calorie counting, no manual logging. Just open the app and see how much fat your body has burned today, during workouts, this week, and over your entire fitness history. HOW IT WORKS FatBurn uses established exercise physiology research to estimate fat oxidation from data already on your iPhone and Apple Watch: Heart rate samples from workouts and throughout the day Your age, weight, and biological sex from Health Workout duration, and intensity Calories are estimated using the Keytel formula (Keytel et al., British Journal of Sports Medicine, 2005). Fat burn is then calculated based on heart rate zone analysis — your body burns a higher percentage of fat at lower intensities and shifts toward carbohydrates at higher intensities. FatBurn classifies your effort into low, moderate, and vigorous zones and applies research-backed fat oxidation percentages to each. WHAT YOU SEE Daily Fat Burn — total fat burned from all activity and resting metabolism Workout Fat Burn — fat burned specifically during recorded workouts Weekly Trends — a 7-day chart showing daily fat burn with weekly totals Workout Breakdown — individual workout cards with fat burn, duration, and calories Lifetime Total — cumulative fat burned from your earliest HealthKit record Customizable Goals — set daily, workout, and weekly fat burn targets based on CDC and AHA guidelines All values display in grams or ounces, with support for kilograms and pounds for larger totals. APPLE WATCH APP FatBurn includes a full Apple Watch companion app so you can check your fat burn stats right from your wrist: Daily and workout fat burn at a glance Active calories, workout minutes, and weekly totals Syncs automatically with your iPhone via HealthKit Designed for quick, on-the-go reference WATCH COMPLICATIONS Add FatBurn to your watch face for instant access. Complications are available in multiple styles and sizes, showing your choice of: Daily Fat Burn Workout Fat Burn Weekly Fat Burn Choose which metric appears on your watch face from the watch app on your iPhone. Complications update throughout the day with HealthKit background delivery. THE SCIENCE FatBurn doesn't just make up numbers. Every calculation is grounded in peer-reviewed research: Keytel Formula for calorie estimation from heart rate (J Sports Sci, 2005) Achten & Jeukendrup's Maximal Fat Oxidation research (Int J Sports Med, 2003) CDC weight loss guidelines (0.5–1.0 kg/week safe range) AHA physical activity recommendations (150 min/week moderate exercise) Full methodology with formulas and citations is available inside the app under Settings. PRIVACY FIRST Your health data stays on your device. Period. FatBurn reads data only from Apple HealthKit on your iPhone and Apple Watch No data is uploaded to any server — all processing happens locally No accounts, no sign-ups, no tracking No third-party analytics or advertising SDKs We cannot see your health data, and we never will FatBurn requires HealthKit access to function. You control exactly which data types you share through the standard iOS Health permissions screen. SUBSCRIPTION FatBurn offers a 1-week free trial with full access to all features. After the trial, continue using FatBurn for $4.99/year. No features are locked — the subscription simply lets you keep using the app you already enjoy. 1-week free trial $4.99/year after trial (price may vary by region) Cancel anytime — no charge if you cancel during the trial Manage or cancel from Settings > Apple ID > Subscriptions DISCLAIMER FatBurn provides estimates based on published exercise physiology formulas. This app is not intended to provide medical advice. Consult a healthcare professional before making health decisions. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

About

Bubbles

Features
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What if your steps kept a tiny fish alive? Bubbles is a pet fish powered by your real walks. Every step feeds it, cheers it up, and unlocks new worlds. Bubbles isn't just an app. It's a tiny companion who needs you. Every step you take in the real world powers Bubbles, keeps the water glowing, and helps your fish thrive. Move more, and Bubbles lights up. Slow down, and Bubbles will miss you. Caring for Bubbles is simple and joyful: - Feed your fish fresh food every day - Keep the water crystal clear to swim in - Watch Bubbles react to your real-world movement - Build a caring streak you'll want to protect - Earn achievements as your bond grows - Unlock beautiful new worlds to explore together Bubbles turns walking into something you actually look forward to. No pressure, no guilt, no complicated charts. Just a sweet little fish who's happier every time you move. Your steps come from Apple Health and stay private. Meet your pet fish worth walking for. Terms of Use (EULA): https://bubbles.fit/legal/terms Privacy Policy: https://bubbles.fit/legal/privacy

Screenshots

Fat Burned4 screens
Bubbles4 screens

Verdict

The call

The clearest difference is iOS requirement: Bubbles at 18.0 against Fat Burned's 26.1. 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Fat Burned sells 1 in-app purchase, starting at $4.99 per year and Bubbles sells 2 in-app purchases, starting at $4.99 per month. Whichever you choose, the download price is not the number that matters.

Scorecard1 real difference · 5 level
Fat Burned versus Bubbles: the parameters behind the verdict, then further details
ParameterFat BurnedBubbles
PriceFreeFree
Update frequency—Every 8 days
AdsNoNo
In-app purchasesYesYes
DevicesiPhone, Apple WatchiPhone, iPad, Apple Watch — better
Requires iOS26.118.0 — better
Further details — not scored
Size3 MB24 MB
Age rating17+12+
DeveloperReliPR, LLCSunil PM

In-app purchases

1 purchases

Fat Burned

Subscriptions1
  • Fat Burned Pro7 Days trial$4.991 Year
2 purchases

Bubbles

Subscriptions2
  • Monthly Premium3 Days trial$4.991 Month
  • Yearly Premium3 Days trial$29.991 Year

Questions

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

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