Wear Radar

Polar Grit XvsFitbit Charge

40d vs 7d
battery life
Polar Grit X lasts longer
$629
price gap
Fitbit Charge cheaper
42g
lighter
Fitbit Charge
2
more health sensors
Fitbit Charge
Polar Grit X
Buy/Wait:bad

Late in cycle — a new model is likely coming

Full details →
Fitbit Charge
Buy/Wait:bad

Late in cycle — a new model is likely coming

Full details →
Polar Grit XFitbit Charge
Pricing
Starting price$749$120
Subscription✓ Noneℹ️ Optional — $79/yr
Hardware
Weight57g15g
Water resistance100m50m
Battery40 days7 days
Always-on display
GPS
Cellular
PlatformiOS & AndroidiOS & Android
TierSports GPSFitness Tracker
Buy timing
ReleasedApr 11, 2024Sep 28, 2023
Cycle advicebadbad
Deals advicegoodgreat
Next modelFitbit Charge 7 (Expected 2026)

Health Sensors

Polar Grit X only
1 exclusive sensor
Running PowerWrist-based watt output — tracks effort independent of terrain
Both
3 shared
Heart RateContinuous or on-demand pulse tracking
SpO2Blood oxygen saturation, tracked during sleep
HRVHeart rate variability — stress & recovery scores
Fitbit Charge only
3 exclusive sensors
ECGDetects irregular heart rhythms (AFib)
EDA / StressSkin conductance sensor measuring stress responses
Skin TempOvernight changes linked to illness or cycle tracking

Why buy each?

Polar Grit X

40-day battery for trail and ultra runners

Five times the battery of the Vantage V3 — enough for week-long mountain stages or ultramarathons without charging access.

Hill splitter auto-detection

Automatically segments your run by uphill and downhill sections, calculating pace and power for each — essential for mountain race training.

Wrist running power at mid-range price

Running power without a chest strap or foot pod — Polar's key differentiator versus Garmin at this price tier.

Fitbit Charge

ECG and EDA stress in a slim band

Full ECG, electrodermal activity stress sensing, SpO2, and continuous heart rate in a tracker thinner than most smartwatches.

Google apps integration

Google Maps navigation, Google Wallet NFC payments, and YouTube Music controls — more useful on-device apps than any previous Charge.

7-day battery with GPS

7 days of typical use, dropping to around 30 minutes per GPS workout session before needing a charge.

Quick Winner

The right pick depends on what you optimize for.

For the budget
Fitbit Charge wins

$357 vs $749 over 3 years · no required subscription.

For battery life
Polar Grit X wins

40 days vs 7 days battery.

For health depth
Fitbit Charge wins

6 sensors.

For daily comfort
Fitbit Charge wins

15g · no required subscription.

Bottom Line

Technical gaps
  1. Grit X-only sensors: Running Power.
  2. Charge-only sensors: ECG, EDA / Stress, Skin Temp.
  3. Weight. Charge is 42g lighter — relevant for all-day comfort and sleep.
  4. Water resistance. Grit X rates 100m vs 50m on Charge.
Commercial gaps
  1. Hardware cost. Charge is $629 cheaper upfront ($120 vs $749).
Pick the Polar Grit X if…

Trail runners, hikers, and outdoor athletes who want Polar's analytics with significantly longer battery life than the Vantage V3. The titanium case and sapphire glass make it suitable for technical terrain where watch durability matters.

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Pick the Fitbit Charge if…

Anyone who wants serious health and fitness tracking without the bulk or cost of a full smartwatch. Works with both Android and iPhone, making it the most accessible Fitbit tracker in the lineup.

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