At a Glance: The Verdict
| Garmin HRM-Fit | Garmin HRM-Pro Plus |
|---|---|
|
Best For: Women who already wear a medium or high-support sports bra Clips directly onto the band of a compatible sports bra, so there is no separate strap around your ribs. Same running dynamics as the Pro Plus, plus HRV data. Costs $149.99 and drops to a 3 ATM water rating. |
Best For: Almost everyone else, especially swimmers and triathletes Standard chest strap that works on any body, any workout. 5 ATM rating handles pool sessions, and store-and-forward memory saves heart rate data when your watch is out of range. Launched at $129.99 and often sells for less. |
Quick Buy Path
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Garmin sells two premium heart rate accessories that feed the same running dynamics into the same watches. The HRM-Pro Plus arrived in July 2022 as the do-everything chest strap. The HRM-Fit landed in January 2024 with a completely different mounting idea: hook it to a sports bra instead of strapping it around your chest.
Key Differences
- How it attaches: The HRM-Fit clips onto the underband of a medium or high-support sports bra. The HRM-Pro Plus uses a traditional adjustable chest strap that fits anyone.
- Water rating: The HRM-Pro Plus is rated 5 ATM. The HRM-Fit is rated 3 ATM, which is a real step down for swim use.
- HRV data: Garmin lists heart rate variability among the HRM-Fit’s sensor outputs. The HRM-Pro Plus spec sheet lists heart rate and the accelerometer for running dynamics only.
- Price: The HRM-Fit launched at $149.99, which is $20 more than the HRM-Pro Plus at $129.99.
- Materials: The HRM-Fit uses a silicone strap. The HRM-Pro Plus uses a plastic module on a fabric strap.
Deep Dive Comparison
Design & Comfort
This is the entire reason the HRM-Fit exists. If you already wear a supportive sports bra, a second elastic band around your ribs is redundant pressure. The HRM-Fit removes that band and clips to the bra you are already wearing. It weighs 53 g against the HRM-Pro Plus at 52 g, so the difference on the scale is nothing. The difference in how it sits on you is the whole point.
The catch is compatibility. The HRM-Fit needs a medium or high-support bra with a band it can grip. Light-support and bralette styles will not hold it. The HRM-Pro Plus has no such requirement. Its 53.7 mm module sits on an adjustable strap and works on any torso, under any shirt, for any user.
Battery Life
Both sensors use a replaceable coin cell rated at 8,760 hours, which is 365 days of typical use. Neither has GPS, so there is no separate GPS battery number to compare. Your watch handles location. These just handle the heart.
Real-world life depends on how many hours per week you train. Heavy users will replace the cell sooner than a year on either device. There is no advantage here for either one.
Health & Fitness Features
Both strap on a chest-based heart rate sensor, which remains more reliable than a wrist optical reading during intervals, cold starts, and anything with heavy arm movement. Both add an accelerometer that produces Garmin’s running dynamics set: cadence, vertical oscillation, ground contact time, ground contact time balance, stride length, and vertical ratio.
Garmin’s spec sheet for the HRM-Fit also lists heart rate variability. The HRM-Pro Plus specs list heart rate and the accelerometer. If HRV capture during a session is something you plan to use, that is a point in the HRM-Fit’s column.
Neither has GPS, a display, a microphone, or a speaker. They are sensors, not watches.
Smart Features
There is no music, no payments, and no notifications on either device. Both connect over ANT+ and Bluetooth, which means both can talk to a Garmin watch and a gym treadmill or a phone app at the same time.
Storage is where they split. The HRM-Pro Plus uses internal store-and-forward memory, so it records heart rate while your watch is off your wrist or out of range, then uploads on reconnect. That is what makes it useful for pool swims and for sports where you do not wear the watch. The HRM-Fit stores up to 18 hours of activity history on-device, so it also covers you when the watch is not listening, but the 3 ATM rating limits how much of that you should spend underwater.
Price & Value
The HRM-Fit launched at $149.99 and the HRM-Pro Plus at $129.99. The HRM-Pro Plus has been on the market since 2022 and shows up discounted far more often than the newer HRM-Fit, so the real-world gap is usually wider than $20.
Spending $20 more to lose a water rating step looks bad on a spec sheet. It is not a bad deal if the bra mount solves a comfort problem that has been keeping you from wearing a chest strap at all. A sensor you actually wear beats a cheaper one sitting in a drawer.
Technical Specs
| Spec | Garmin HRM-Fit | Garmin HRM-Pro Plus |
|---|---|---|
| Release Date | January 8, 2024 | July 13, 2022 |
| Launch Price | $149.99 | $129.99 |
| Weight | 53 g | 52 g |
| Module Size | Not published | 53.7 mm |
| Material | Silicone strap | Plastic |
| Water Rating | 3 ATM | 5 ATM |
| Display | None | None |
| Battery | 8,760 hours (365 days) | 8,760 hours (365 days) |
| GPS | None | None |
| Connectivity | ANT+, Bluetooth | ANT+, Bluetooth Low Energy |
| Sensors | Heart rate, HRV, accelerometer (running dynamics) | Heart rate, accelerometer (running dynamics) |
| Storage | Up to 18 hours of activity history | Internal (store-and-forward) |
| NFC Payments | No | No |
The Verdict
The Garmin HRM-Pro Plus is the better buy for most people. It costs $20 less at list, works on any body without a wardrobe requirement, carries the higher 5 ATM water rating, and its store-and-forward memory covers swim and non-watch workouts properly. Nothing about it is dated. It produces the same running dynamics the HRM-Fit does.
Buy the HRM-Pro Plus if you swim, you race triathlon, you share the sensor with a partner, or you simply want the widest compatibility for the lowest price.
Buy the HRM-Fit if you train in a medium or high-support sports bra and a chest strap has been the thing stopping you from using one. The bra mount removes a second band from your ribcage, and the HRM-Fit adds HRV to the data set. Accept the 3 ATM rating and skip it if the pool is a regular part of your week.
Frequently Asked Questions
Which one is more accurate?
Neither has an accuracy advantage on paper. Both are chest-position electrical heart rate sensors feeding the same Garmin watches, and both deliver the same running dynamics metrics. Accuracy comes down to placement and contact, not the model you pick.
Can I swim with the HRM-Fit?
It is rated 3 ATM, which is lower than the HRM-Pro Plus at 5 ATM. If pool sessions are part of your routine, buy the HRM-Pro Plus instead. Its 5 ATM rating and store-and-forward memory are built for exactly that workout.
Is the HRM-Fit worth $20 more than the HRM-Pro Plus?
Only if the sports bra mount solves a comfort problem for you. If a standard chest strap is fine on your body, you are paying more for a lower water rating and a narrower fit requirement. The extra HRV data does not close that gap by itself.
Do these work with an iPhone or Android phone?
Both broadcast over ANT+ and Bluetooth, so both pair with phone apps and gym equipment as well as Garmin watches. Bluetooth is the connection your phone will use on either platform. ANT+ handles the Garmin watch and compatible cardio machines at the same time.
Do I need a Garmin watch to use either one?
No, but you get the most out of them with one. Running dynamics metrics like ground contact time and vertical oscillation are recorded and displayed through Garmin’s ecosystem. Paired with a third-party app over Bluetooth, you will get heart rate and not much else.
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Specs and features may change. Always verify details on the manufacturer’s official site before purchasing.
