The best weight trend apps 2026 compared

In short

A weight trend app smooths the daily swings of your scale into a calm line. For iPhone and Android without an account, Trendcurve fits; Libra also runs on both, with a cloud account and ads in the free version. Happy Scale is available for Apple devices only. TrendWeight and The Hacker's Diet Online run free in the browser. MacroFactor is worth it if you also want to count calories and macros.

Disclosure: this page is made by the makers of Trendcurve. We have tried to compare fairly, say for each app who it suits better, and back every claim about other apps with a source. Prices are from the US App Store and may differ by country.

The apps at a glance

App iPhoneAndroidBrowserGoal dateGLP-1 doseNo accountFree version
Trendcurve
Happy Scale
Libra
MacroFactor
TrendWeight
The Hacker's Diet Online
Withings

Goal date in Trendcurve is part of Pro. "?" means: no information found. Details and sources are listed for each app below.

Which app is right for you?

  • Android and iPhone without an account: Trendcurve: four trend methods to choose from, data stays on your device, import from Happy Scale and Libra.
  • Apple devices only, including iPad and Mac: Happy Scale: mature, with milestone goals and sync between iPhone and iPad.
  • Free in the browser: TrendWeight with a Withings scale or manual entry, or The Hacker's Diet Online, the original of the trend method.
  • With calorie and macro counting: MacroFactor: a nutrition coach with a weight trend, no free version.
  • On a weight loss injection (GLP-1): Trendcurve: dose markers and an injection day reminder for free, weekly rate per dose level with Pro. We found no dose feature in the other apps.

How we compared

We included apps and web tools whose core is a smoothed weight trend, not just a list of readings. We checked the official websites, help pages and store listings. Where we found nothing, the table says "no information found", even if the app may have the feature.

  • Platforms: iPhone, Android or browser
  • Trend smoothing: which method, and whether you can choose it
  • Forecast: whether the app calculates when you will reach your goal
  • GLP-1: whether you can log the dose or injection of a weight loss medication
  • Account: whether you have to sign up and where your data is stored
  • Price and languages

The apps in detail

1. Trendcurve

A good fit if you use an iPhone or Android, do not want an account and want to choose the trend method yourself. Also for a weekly weight loss injection.

Platforms iPhone and Android
Trend smoothing Four methods to choose from: exponential smoothing (default), 7-day or 14-day moving average, double exponential smoothing
Forecast and goal date Goal date from your current weekly rate, planned vs. measured (Pro)
GLP-1 and medication Dose markers and a weekly injection reminder (free), weekly rate per dose level (Pro)
Account and data No account, no own server, no ads; weigh-ins stay on your device. On iPhone an optional backup to your own iCloud account (Pro)
Pricing Free; Pro as a monthly or yearly subscription or a one-time purchase
Languages 10 languages: German, English, French, Spanish, Italian, Portuguese, Dutch, Swedish, Norwegian, Danish

Download on the App Store · Get it on Google Play

2. Happy Scale

A good fit if you only use Apple devices and want your data synced between iPhone and iPad.

Platforms iPhone, iPad and Mac with Apple silicon; no Android version found
Trend smoothing Moving average, with several options according to the developer; the exact formula is not published
Forecast and goal date Yes: predicts your future weight at your current pace
GLP-1 and medication no information found
Account and data Data stored on the device by default, no server login; sync via iCloud or Dropbox available
Pricing Free download; in the US App Store Deluxe costs $1.99 a month, $11.99 a year or $39.99 one-time
Languages 10 languages: English, Chinese (Simplified), French, German, Italian, Japanese, Korean, Portuguese, Russian, Spanish

Website: Happy Scale · Detailed comparison: Trendcurve and Happy Scale

3. Libra

A good fit if you want an Android app with cloud backup and do not mind ads in the free version.

Platforms Android, iPhone and iPad, Mac with Apple silicon
Trend smoothing Exponential smoothing, strength adjustable (default: 7 days)
Forecast and goal date Yes: linear regression over the trend values (default: 7 days)
GLP-1 and medication no information found
Account and data Libra Cloud account: according to the developer, profile and weight history are also stored on its servers; online backups and sync
Pricing Free with ads; Pro without ads in the US App Store for $1.99 a month or $17.99 a year
Languages App Store: English; Google Play: no information found

Website: Libra · Detailed comparison: Trendcurve and Libra

4. MacroFactor

A good fit if you count calories and macros and want a nutrition plan that adjusts every week.

Platforms iPhone, iPad, Apple Watch, Mac with Apple silicon and Android
Trend smoothing Weighted average over a longer period, recent values count more
Forecast and goal date no information found
GLP-1 and medication no information found
Account and data According to the App Store privacy details, health data, email address and purchases, among others, are linked to your identity
Pricing No free version, 7-day trial; in the US App Store $11.99 a month, $47.99 per half year or $71.99 a year, different in other countries
Languages App Store: English and Japanese

Website: MacroFactor · Detailed comparison: Trendcurve and MacroFactor

5. TrendWeight

A good fit if you have a Withings scale or want to log in the browser without installing an app.

Platforms Web app in the browser, also on your phone; according to the developer, no native app is planned
Trend smoothing Exponential smoothing as in The Hacker's Diet, factor 0.1
Forecast and goal date Yes: the date you will reach your goal at your current rate
GLP-1 and medication no information found
Account and data Account with sign-in by email code, passkey or Google, Apple, Microsoft; weights from Withings, Fitbit (until September 2026 according to the developer) or manual entry
Pricing Free, optional tip jar
Languages Website in English

Website: TrendWeight

6. The Hacker's Diet Online

A good fit if you want to use the method from John Walker's book The Hacker's Diet in its original form.

Platforms Web app in the browser, with a view for small screens
Trend smoothing Smoothed trend as in The Hacker's Diet, weekly rate by linear regression
Forecast and goal date Diet calculator with an end date, plan drawn as a line in the chart
GLP-1 and medication no information found
Account and data Account with user name, password and email; data on the Fourmilab server, export as CSV or XML
Pricing no information found; the source code is in the public domain
Languages English; weight in kg, pounds or stones

Website: The Hacker's Diet Online

7. Withings

A good fit if you use a Withings scale and want weight, body composition and other readings in one app.

Platforms iPhone, iPad, Mac, Apple Watch and Android
Trend smoothing Trend line in the weight chart; according to Withings support, the exact algorithm is not published
Forecast and goal date no information found
GLP-1 and medication Withings promotes body composition scales for people on GLP-1; we found no dose logging
Account and data Scale and data are tied to a Withings account
Pricing Free; Withings+ in the US App Store for $9.99 a month or $99.99 a year
Languages 21 languages according to the App Store

Website: Withings

Try Trendcurve for free

For iPhone and Android, no account needed. Your weigh-ins stay on your device.

Frequently asked questions

An app that turns your daily readings into a smoothed trend, usually with a moving average or exponential smoothing. Water, salt and digestion make the scale swing by one to two kilos (2 to 4 lb); the trend shows whether your weight is really going down, up or staying the same.

No, we found no Android version. According to the App Store, Happy Scale runs on iPhone, iPad and Mac. On Android, Trendcurve and Libra show you a weight trend, and Trendcurve also imports the CSV file from Happy Scale.

Trendcurve, Happy Scale, Libra and the Withings app have a free version; Libra shows ads in it. TrendWeight is a free web app. MacroFactor has no free version, only a trial.

Trendcurve records dose levels, reminds you on injection day and, with Pro, shows the weekly rate per dose level. In the other apps in this comparison we found no feature for logging the dose of a weight loss injection.

No, it is made by the makers of Trendcurve. That is why we back every claim about other apps with a source, say for each app who it suits better, and write "no information found" where we could not check something.

Sources

Checked in October 2026. The information about Happy Scale, Libra and MacroFactor comes from the sources of their comparison pages, the rest from these pages:

Trademarks belong to their owners. Trendcurve is not affiliated with the apps, websites or publishers mentioned.

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