What matters

These are two sizes of the same watch, not two performance tiers. Because their processor, memory, storage, sensors, health software, durability, and mode-specific endurance ceilings are shared, wrist fit and usable display area should decide the purchase.

Key differences

  • Both Bluetooth models use Snapdragon Wear Elite with 2 GB RAM, 32 GB storage, an up-to-3000-nit sapphire Super AMOLED display, the same sensors and dual-frequency GPS, 5ATM, IP68, and a military-grade durability standard. Neither has cellular service.
  • The 40mm body measures 42.7 by 40.4 by 8.6 mm and weighs 31.5 g without its band. It pairs a 1.34-inch 438 by 438 display with a 390 mAh battery.
  • The 44mm body measures 46.0 by 43.7 by 8.6 mm and weighs 34.0 g without its band. It pairs a 1.47-inch 480 by 480 display with a 445 mAh battery.
  • Samsung US lists the 40mm Bluetooth at USD 379.99 and the 44mm Bluetooth at USD 409.99. Despite the USD 30 gap and different capacities, Samsung claims the same ceilings for both: up to 40 hours with the always-on display off or 30 hours with it on.

Who it is for

  • Choose 40mm if a smaller case reduces wrist coverage enough to improve comfort, especially for sleep tracking or smaller wrists. You also keep the lower purchase price without giving up the shared platform.
  • Choose 44mm if the larger screen makes maps, text, and touch targets materially easier to use. That operational gain, not the larger battery by itself, is the reason to accept more wrist coverage, weight, and cost.
  • Resolve phone and service needs before size. Both watches have the same Bluetooth-only connectivity and health boundaries, so changing case size cannot fix an incompatible phone, unsupported country, or need for cellular independence.

Watch-outs

  • Do not infer a runtime winner from 390 mAh versus 445 mAh: the larger battery also drives the larger display, and Samsung gives both sizes the same mode-specific endurance ceiling rather than matched independent results.
  • Samsung Health Monitor requires a supported country, account, and compatible Samsung Galaxy phone. Blood-pressure estimates also need calibration with a separate upper-arm cuff and are not a diagnosis.
  • Hidden costs can overwhelm the USD 30 size gap: a replacement band, upper-arm cuff, compatible Samsung phone, or move to an LTE model and service are separate expenses. Buy neither Bluetooth size for iPhone use, dependable multi-day endurance, cellular independence, or medical diagnosis.