Garmin Forerunner 45 vs Forerunner 45S
Size, specs & wrist fit compared
Which one fits you
Under 15 cm (5.9 in) round, the 42mm's lugs overhang and the 39.5mm's do not; the 39.5mm fills the wrist at 15–16.5 cm, the 42mm at 16–17.5 cm.
What else differs
- Battery: about 7 days each in everyday use; about 13 hours each with GPS on.
The Forerunner 45 is 2.5mm wider than the Forerunner 45S.
Forerunner 45
Forerunner 45S
Case width
42mm
39.5mm−2.5mm
Thickness
11.4mm
11.4mmsame
Weight
32g
32gsame
Forerunner 45: 42mm or 39.5mm by wrist size
| Wrist round (mm left each side) | 42mm≈48.5mm lug to lug, est. | 39.5mm≈45.5mm lug to lug, est. |
|---|---|---|
| 14 cm / 5.5 in | Overhangs (1.7mm over) | Overhangs (0.2mm over) |
| 15 cm / 5.9 in | Overhangs (0.1mm over) | Sweet spot (1.4mm) |
| 16 cm / 6.3 in | Sweet spot (1.6mm) | Sweet spot (3.1mm) |
| 17 cm / 6.7 in | Sweet spot (3.2mm) | Balanced (4.7mm) |
| 18 cm / 7.1 in | Balanced (4.8mm) | Balanced (6.3mm) |
| 19 cm / 7.5 in | Balanced (6.4mm) | Balanced (7.9mm) |
| 20 cm / 7.9 in | Balanced (8mm) | Balanced (9.5mm) |
Switch or add watches
Garmin
Forerunner 45
Garmin
Forerunner 45S
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Battery life compared
Forerunner 45Forerunner 45S
Smartwatch
7 days7 daysGPS only
13 hours13 hours
2D Dimension Schematics
- Garmin Forerunner 45 42mm × ≈48.5mm (est.) · 11.4mm thick
- Garmin Forerunner 45S 39.5mm × ≈45.5mm (est.) · 11.4mm thick
3D preview
Forerunner 45 vs Forerunner 45S on a wrist
Specifications
The short version
7 key specs| Spec | GarminForerunner 45 | GarminForerunner 45S |
|---|---|---|
| Case Width | 42mm | 39.5mm |
| Thickness | 11.4mm | 11.4mm |
| Weight | 32g | 32g |
| Shape | Circular | Circular |
| Display type | Sunlight-visible, transflective memory-in-pixel (MIP) | Sunlight-visible, transflective memory-in-pixel (MIP) |
| Battery life | Smartwatch Mode: Up to 7 days GPS mode: Up to 13 hours | Smartwatch Mode: Up to 7 days GPS mode: Up to 13 hours |
| Released | 2019 | 2019 |
Where the specifications differ
4 differences| Spec | Garmin Forerunner 45 | Garmin Forerunner 45S |
|---|---|---|
| Product Info | ||
| Main SKU | 010-02156-05 | 010-02156-00 |
| Product ID | 641121 | 682416 |
| Product Name | Forerunner® 45 | Forerunner® 45S |
| Product Variation | Black | White |
The other 82 specifications both list are identical.
Full Garmin Forerunner 45 specifications →Full Garmin Forerunner 45S specifications →