Comparison

Scale Relay vs Longevity Arc

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

Head to head
About

Scale Relay

Read full description

Get your smart scale's weigh-ins into Garmin Connect, straight from your iPhone. Two ways in, one tap out. APPLE HEALTH ROUTE: ANY SCALE If your scale's app saves weight to the Health app, Scale Relay picks it up and sends it to Garmin Connect. Works with Withings, Renpho, Eufy, Etekcity, Zepp Life, Wyze, Picooc and any other app that writes weight to Apple Health. Body fat and BMI come along when your scale's app provides them. BLUETOOTH ROUTE: XIAOMI SCALES, NO OTHER APP NEEDED Step on a Mi Body Composition Scale 2 or a Xiaomi Body Composition Scale S400 and Scale Relay reads the measurement directly: weight, body fat, muscle mass, bone mass, water, BMI and BMR. The S400 needs a one-time authorization with your Xiaomi account. WHAT YOU GET โ€ข A preview of every weigh-in before it is sent; nothing leaves without your tap โ€ข Body composition in Garmin Connect, not just the weight โ€ข Weigh-ins from the last 7 days are included; Garmin Sync unlocks older history โ€ข One Garmin sign-in, two-factor authentication supported โ€ข A "Sent to Garmin" list so you know what arrived FREE TO TRY Your first two syncs are free on either route. Unlimited syncing is a single one-time purchase called Garmin Sync. No subscription. PRIVACY FIRST Your measurements stay on your iPhone and go only to your own Garmin account. No Scale Relay account, no tracking, no ads. REQUIREMENTS โ€ข iOS 17 or later โ€ข A Garmin Connect account โ€ข Apple Health route: any scale app that writes weight to the Health app โ€ข Bluetooth route: Mi Body Composition Scale 2 or Xiaomi Body Composition Scale S400 Scale Relay is an independent app. It is not affiliated with, endorsed by or associated with Garmin, Xiaomi, Withings, Renpho, Eufy, Etekcity, Zepp, Wyze, Picooc or any other scale or fitness-platform maker. Product names are trademarks of their respective owners.

About

Longevity Arc

Features
Read full description

Longevity Arc turns your Apple Health data into five clear longevity signals. Instead of digging through scattered charts, you can see HRV, fitness, sleep, gait, and cardiac load together in one simple dashboard designed to help you understand how your body is trending over time. Built for people who care about healthspan, recovery, and long-term performance, Longevity Arc helps you spot changes faster and focus on the metrics that matter most. The app is designed to feel simple at a glance while still giving you useful depth when you want to explore trends and patterns. What you can do in Longevity Arc: - Track five science-inspired longevity signals from Apple Health in one place. - Review your HRV, sleep, fitness, gait, and cardiac-load trends without jumping between different screens. - Get a clearer picture of how daily habits may affect your long-term trajectory. - Use a private, HealthKit-powered experience built around your own data. Why people use Longevity Arc: - Apple Health already contains valuable signals, but they are often fragmented and hard to interpret quickly. - Longevity Arc brings those signals together into a more readable view so you can check your status in seconds. - The focus is not noise or endless scores - it is a cleaner way to monitor meaningful change over time. Privacy and data: - Longevity Arc works with your Apple Health data. - You stay focused on your own signals, trends, and progress. Ideal for: - Biohackers tracking recovery and resilience. - Health-conscious users who want a simpler Apple Health dashboard. - Founders, athletes, and everyday users trying to balance stress, fitness, and sleep over time. Privacy Policy: https://longevityarc.app/privacy Terms of Use: https://longevityarc.app/terms

Screenshots

Scale Relay4 screens
Longevity Arc4 screens

Verdict

The call

The clearest difference is update cadence: Longevity Arc at every 3 days against Scale Relay's weekly. Longevity Arc also leads on device support (3 vs 1) and iOS requirement (15.1 vs 17.0). On price, ads and in-app purchases there is nothing between them.

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. Scale Relay sells 1 one-off in-app purchase and Longevity Arc sells 2 in-app purchases, starting at $2.99 per month. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Scale Relay ships an update weekly, Longevity Arc every 3 days. The most recent releases landed on October 6, 2026 and October 7, 2026 respectively.

Scorecard3 real differences ยท 3 level
Scale Relay versus Longevity Arc: the parameters behind the verdict, then further details
ParameterScale RelayLongevity Arc
PriceFreeFree
Update frequencyWeeklyEvery 3 days โ€” better
AdsNoNo
In-app purchasesYesYes
DevicesiPhoneiPhone, iPod, Apple Watch โ€” better
Requires iOS17.015.1 โ€” better
Further details โ€” not scored
Size1 MB40 MB
Age rating4+4+
DeveloperMarcin NaglikRadoslaw Jozefowicz

In-app purchases

1 purchases

Scale Relay

One-time1
  • Garmin Export$9.99
2 purchases

Longevity Arc

Subscriptions1
  • Monthly Pro3 Days trial$2.991 Month
One-time1
  • Lifetime Pro$9.99

Questions

Is Scale Relay free?
Scale Relay is free to download, with in-app purchases available.
Is Longevity Arc free?
Longevity Arc is free to download, with in-app purchases available.
Do Scale Relay or Longevity Arc have ads?
Neither Scale Relay nor Longevity Arc shows ads.
Which is updated more often, Scale Relay or Longevity Arc?
Scale Relay ships an update weekly, and Longevity Arc every 3 days. Most recently, Scale Relay was updated on October 6, 2026 and Longevity Arc on October 7, 2026.

Other comparisons