No. Body Battery is a Garmin feature, and the Fitbit Air does not have it or a copy of it. The nearest thing in the Google Health app is Daily Readiness, a single score you get once each morning. It answers a related question, but it doesn’t rise and fall through the day the way Body Battery does.
If you are choosing between the two bands rather than looking for the score, the Fitbit Air vs Garmin Cirqa comparison sets their scores side by side.
What Body Battery actually is
Garmin’s owner’s manuals describe Body Battery as an estimate of your available reserve energy, “like a gas gauge on a car”. The manual lists four inputs: heart rate variability, stress, sleep and activity. It runs from 5 to 100, with Garmin’s own bands being 5 to 25 very low, 26 to 50 low, 51 to 75 medium and 76 to 100 high.
The part that matters for this comparison is that it is a running gauge. Sleep and rest charge it. Stress and exertion drain it. Garmin’s tips page says the opposite of what people often assume about food: eating and caffeine have no effect on it. The level refreshes when the watch syncs.
Garmin doesn’t publish the formula. Third-party write-ups say it comes from Firstbeat Analytics, the heart-data company Garmin bought in 2020, and the same engine sits behind Garmin’s all-day stress score. No peer-reviewed study was found that checks Body Battery against an outside measure, so treat it as a modelled estimate, not a measurement.
What the Fitbit Air and Google Health give you
The Fitbit Air is a screenless band that launched in May 2026. Its data goes to the Google Health app (the renamed Fitbit app). Google’s help page for Readiness lists the Air as supported, with two details worth knowing:
- Readiness is a 100-point score built from three things: sleep patterns over the past week, heart rate variability and resting heart rate. Activity is no longer a direct input.
- It is calculated once a day, shortly after you get up from a sleep of at least 3 hours. You need 7 nights of wear before the first score, and about a month for a more accurate baseline.
Google’s bands are Low (29 or below), Moderate (30 to 64) and High (65 and above). The help page says the scale runs 0 to 100 in one place and 1 to 100 in another, which is a small thing but worth knowing if you ever see a 0.
No Body Battery-style metric appears anywhere in Google’s list of health metrics, so none exists as of October 2026. Google also doesn’t send its Readiness score through the Google Health API that third-party apps use, which is why other tools can’t simply display it.
Side by side
| Garmin Body Battery | Google Daily Readiness | |
|---|---|---|
| Updates | Through the day, on sync | Once, after you wake |
| Range | 5 to 100 | 0 or 1 to 100 |
| Inputs (as published) | HRV, stress, sleep, activity | Sleep (past week), HRV, resting heart rate |
| Reacts to your day | Yes, drains with stress and activity | No. Activity is not a direct input |
| Formula published | No | No, inputs only |
So if you wake up with a Body Battery of 82 on a Garmin and a Readiness of 71 on a Fitbit, those two numbers aren’t two readings of one thing. Body Battery’s morning value is mostly about how well the night recharged you. Readiness is about how your body has been trending against your own baseline.
The closest match depends on what you miss
People usually ask for a Body Battery equivalent because they miss one of two things.
You want a morning “how recovered am I” number. Daily Readiness is the right match. On Garmin the closer comparison is actually Training Readiness, not Body Battery, because Training Readiness is also a morning-style verdict built from sleep, HRV status and recent load. If that’s your question, Fitbit readiness always low? Check these 6 things covers what moves it.
You want a gauge that drains through the day. Nothing in the Google Health app does this. You can approximate it by hand, by watching your heart rate and stress-like signals during the day, but that is not a number.
One further limit: the Air has no screen, so even Readiness lives in the phone app. A Pixel Watch can show it on the wrist, but Google’s page doesn’t list the Air for on-device display.
A way to get the running gauge
Pulse, a free app you host yourself, computes an Energy Bank figure from your Google Health data. It starts each morning at 60% of that day’s Recovery plus 40% of last night’s Sleep Performance, then subtracts minute by minute for being awake, for heart-rate load and for high-stress minutes, and adds back a little for calm, still minutes and naps (how Energy Bank works).
That is Pulse’s own model, not Garmin’s, and the constants are tuned by hand rather than validated. Pulse needs Docker and your own Google Cloud project, and it has been tested on the Fitbit Air only. Other devices that sync to Google Health send the same data types but haven’t been tried.
Why Google may have left it out
This is a guess, since Google hasn’t said. A running gauge needs a model of what each minute of the day costs you, and that model is hard to validate. Garmin’s version has no published accuracy figure either. Google’s choice to keep Readiness as a once-a-day score built from sleep, HRV and resting heart rate is at least easy to explain: those are three signals with a clear link to recovery.
What to do with this
- Decide which Body Battery behaviour you want. If it is the morning verdict, use Readiness and give it its month of baseline.
- Don’t compare absolute numbers across brands. An 80 on one scale means nothing on the other.
- Look at the trend. Garmin’s own manual points you to Garmin Connect for long-term trends, and the same logic applies to Readiness: three low mornings in a row says more than one.
- Wear the band to sleep every night. Both systems lean on overnight heart rate variability, and both depend on a night of clean data.
If you are choosing hardware and Body Battery matters to you, Garmin’s screenless Cirqa band is the Garmin route. Its feature list was not checked in detail here, so look at Garmin’s own page before buying.