Scale Relay
Fitdays scale to Garmin Connect on iPhone
Fitdays is the app behind a long list of inexpensive body-fat scales: Posture, Healthkeep, ABLEGRID and dozens of unbranded models whose Amazon listing just says "download the Fitdays app". It syncs with Apple Health, Google Fit and Fitbit, but not with Garmin Connect. On an iPhone Scale Relay fills that gap: Fitdays writes each weigh-in to Apple Health, Scale Relay reads it there and sends it to Garmin. Here is the setup, what arrives in Garmin, and the usual fixes.
What you need
- A scale that pairs with the Fitdays app (or Fitdays+), made by ICOMON. The scale's box or Amazon listing names the app; brands include Posture, Healthkeep, ABLEGRID and many unbranded "smart body fat scales".
- An iPhone with iOS 17 or later. Scale Relay reads Apple Health, which only exists on iPhone.
- A Garmin Connect account. Two-factor authentication is supported.
- Scale Relay from the App Store. The first two syncs are free.
Free to try. The first two syncs are free and include weigh-ins from the last 7 days. Unlimited syncing and older history are a one-time $14.99 purchase (Garmin Sync), no subscription.
How it works
Garmin Connect does not read weight from Apple Health, and Fitdays has no Garmin option. Scale Relay closes the gap from the Health side: Fitdays keeps writing each weigh-in to Apple Health as it does today, Scale Relay lists what is new, and one tap sends those weigh-ins to Garmin Connect. Garmin shows them under Health Stats › Weight, like a weigh-in from a Garmin Index scale.
Scale Relay relays only what Fitdays actually wrote. Weight is always there. Body fat percentage and BMI arrive when Fitdays writes them to Health; which categories it writes depends on the app version and on what you allowed, and the Health app shows you exactly that. Muscle mass, water and bone mass have no Apple Health type, so they stay in Fitdays.
Make sure Fitdays writes to Apple Health
In Fitdays, open the Me tab (your profile), then Settings and look for Apple Health; the wording moves between versions, so it may sit under a "Sync" or "Third-party" heading. Turn it on and allow every category iOS offers. Fitdays' App Store description confirms that weigh-ins taken with the scale sync to Apple Health once connected.
If you dismissed the iOS permission screen earlier, fix it in the Health app: tap your profile picture, then Apps › Fitdays, and turn on Weight plus Body Fat Percentage and Body Mass Index if they are listed. Then weigh yourself once more; Fitdays writes new weigh-ins, not earlier ones.
Fitdays supports up to 24 family members. Only the profile that is selected when you step on the scale gets the weigh-in, and only that iPhone's Health gets a copy; a visitor measurement is not saved at all.
Step by step
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Weigh yourself with Fitdays open
Open Fitdays on your iPhone, make sure your own profile is selected, and step on the scale barefoot. The app receives the measurement over Bluetooth, calculates body composition and writes the weigh-in to Apple Health.
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Confirm the weigh-in is in Health
Only needed the first time. In the Health app, Browse › Body Measurements › Weight should show today's weight with Fitdays as its source. If not, go back to the section above.
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Install Scale Relay and connect Apple Health
Download Scale Relay from the App Store, open the Health tab and tap Connect Apple Health. iOS shows the Health permission screen: allow Weight, Body Fat Percentage and Body Mass Index. Scale Relay only reads on this route; it never changes what is in Health.
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Check the source and connect Garmin
Scale Relay picks the app that saved your most recent weigh-in as the source; if you have several scale apps, choose Fitdays from the Source menu. Tap Connect next to Garmin Account and sign in with your Garmin email and password; enter the code if your account uses two-factor authentication.
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Review and send
The New measurements list shows every weigh-in Fitdays saved to Health in the last 7 days, with body fat and BMI next to each one when the app wrote them. Tap Send to Garmin. Scale Relay confirms each accepted upload; find them in Garmin Connect under Health Stats › Weight. Nothing is ever sent twice, and nothing is sent without that tap.
Ready to try it? Get Scale Relay on the App Store; the first two Garmin syncs are free.
What is transferred
| Metric | In Apple Health | Sent to Garmin Connect |
|---|---|---|
| Weight | Always | Yes |
| Body fat % | When Fitdays wrote it | Yes |
| BMI | When Fitdays wrote it | Yes |
| Muscle mass, body water, bone mass, BMR | No Apple Health type; stays in Fitdays | No |
| Date and time | The weigh-in's own time | The moment you weighed |
A weight that is younger than a minute waits until Fitdays has written its companion body fat and BMI, so a weigh-in never reaches Garmin as weight only when the full set is on its way. If Fitdays writes weight only on your phone, Garmin gets weight only; the Health app's Apps › Fitdays screen shows which categories the app asked for.
Already have months of weigh-ins?
Scale Relay sends weigh-ins from the last 7 days before you connected, and everything older that Fitdays has written to Health once Garmin Sync is unlocked (Include older measurements on the Health tab). For history from before Health access, export your data from Fitdays if your version offers it and convert the file with the free Garmin Connect weight import tool using its spreadsheet option.
Where to buy
- Posture smart scale: a popular Fitdays-based scale; weight, body fat and BMI through Apple Health and Scale Relay.
Troubleshooting
The Health tab shows "No weight data found"
- Open the Health app › profile picture › Apps › Fitdays and make sure Weight is on. If Scale Relay is listed there, make sure its Weight switch is on too.
- Check that Apple Health is turned on inside Fitdays (Me › Settings).
- Weigh yourself once more with Fitdays open; the app does not back-fill weigh-ins made before access was granted.
- Pull down on the Health tab to refresh the list.
The weigh-in is listed but has no body fat
Body composition needs a barefoot measurement with dry feet; in socks the scale reports weight only. If barefoot weigh-ins still arrive as weight only, Fitdays on your phone writes weight alone to Health: check Health › Apps › Fitdays for Body Fat Percentage and Body Mass Index switches.
The wrong family member's weight arrived
Fitdays attributes a weigh-in to the profile that was selected in the app. Select your own profile before stepping on, or let Fitdays' automatic recognition pick you by weight. Scale Relay sends whatever Fitdays wrote to this iPhone's Health.
Garmin sign-in or upload problems
- Use your Garmin account email and password, and enter the two-factor code when asked; codes expire quickly.
- Repeated failed sign-ins are temporarily blocked by Garmin. Wait a few minutes.
- A failed upload stays queued: open Scale Relay and tap Retry. Nothing is sent in the background.
- Garmin China (garmin.cn) accounts are separate from connect.garmin.com and are not supported.
Frequently asked questions
Does Fitdays sync with Garmin Connect?
No. Fitdays connects to Apple Health, Google Fit and Fitbit. On an iPhone, Apple Health plus Scale Relay carries weight, and body fat and BMI when Fitdays writes them, to Garmin Connect.
My scale came with a different app. Does this still apply?
If your scale uses Fitdays or Fitdays+, yes. Many scales from the same factories ship with other apps, such as OKOK, Feelfit or Starfit; as long as that app writes weight to Apple Health, the same Scale Relay steps work. The Apple Health guide covers the general case.
Do I need to keep the Fitdays app?
Yes. The scale sends its measurement to Fitdays, which calculates body composition and writes to Health. Scale Relay does not talk to the scale on this route; it reads what Fitdays wrote.
Will body fat and muscle show up in Garmin?
Body fat percentage and BMI do, when Fitdays writes them to Health. Muscle mass, water and bone mass have no Apple Health type, so they stay in Fitdays. A Xiaomi scale over Scale Relay's Bluetooth route carries the full set if you want everything in Garmin.
Is it automatic?
No. Scale Relay reads Health and sends when you open the Health tab and tap Send; iOS does not let a third-party app watch Health in the background. Weigh in, open the app, tap once.
What does it cost?
The app is free, the first two syncs are free, and unlimited syncing plus older history is a one-time $14.99 purchase called Garmin Sync. No subscription, no account.
Is there an Android version?
No. Scale Relay is an iPhone app because this route depends on Apple Health. On Android, look at the options compared page for tools that work there.
Is my data private?
Weigh-ins go from Apple Health on your iPhone straight to your Garmin account. Scale Relay has no server of its own, no account and no analytics; the privacy section has the details.
Get Scale Relay
Keep Fitdays, add Garmin Connect. Two syncs are free, then a one-time $14.99 purchase.
Download on the App StoreIndependent app. Not affiliated with Garmin, Apple or ICOMON (Fitdays).
