Garmin Fenix 8 51mm AMOLED vs Instinct E 45mm
Size, specs & wrist fit compared
Which one fits you
Under 18 cm (7.1 in) round, the Fenix 8 51mm AMOLED's lugs overhang and the Instinct E 45mm's do not; the Instinct E 45mm fills the wrist at 17–19 cm, the Fenix 8 51mm AMOLED at 19 cm and up.
What else differs
- Screen: the Fenix 8 51mm AMOLED uses a bright AMOLED screen, the Instinct E 45mm a memory-in-pixel screen that is easy to read in sunlight and sips battery.
- Battery: 29 days for the Fenix 8 51mm AMOLED against 16 days for the Instinct E 45mm in everyday use; 3.5 days for the Fenix 8 51mm AMOLED against 24 hours for the Instinct E 45mm with GPS on.
Among the 52 smartwatches 51mm across that we hold thickness for, the Fenix 8 51mm AMOLED is thinner than 98%, so it wears flatter than its width suggests.
The Fenix 8 51mm AMOLED is 6mm wider, 0.5mm thicker and 54g heavier than the Instinct E 45mm.
Fenix 8 51mm AMOLED
Instinct E 45mm
Case width
51mm
45mm−6mm
Thickness
14.7mm
14.2mm−0.5mm
Weight
102g
48g−54g
Fenix 8 51mm AMOLED or Instinct E 45mm by wrist size
| Wrist round (mm left each side) | Fenix 8 51mm AMOLED≈58.5mm lug to lug, est. | Instinct E 45mm≈51.5mm lug to lug, est. |
|---|---|---|
| 14 cm / 5.5 in | Overhangs (6.7mm over) | Overhangs (3.2mm over) |
| 15 cm / 5.9 in | Overhangs (5.1mm over) | Overhangs (1.6mm over) |
| 16 cm / 6.3 in | Overhangs (3.4mm over) | Bold (0.1mm) |
| 17 cm / 6.7 in | Overhangs (1.8mm over) | Sweet spot (1.7mm) |
| 18 cm / 7.1 in | Overhangs (0.2mm over) | Sweet spot (3.3mm) |
| 19 cm / 7.5 in | Bold (1.4mm) | Balanced (4.9mm) |
| 20 cm / 7.9 in | Sweet spot (3mm) | Balanced (6.5mm) |
Switch or add watches
Garmin
Fenix 8 51mm AMOLED
Garmin
Instinct E 45mm
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Battery life compared
Furthest apart in All systems mode, where the Fenix 8 51mm AMOLED lasts 4.3× as long as the Instinct E 45mm (2.8 days against 16 hours).
Fenix 8 51mm AMOLEDInstinct E 45mm
Battery saver
41 days40 daysExpedition
31 days20 daysSmartwatch
29 days16 daysMax battery GPS
145 hours50 hoursGPS only
84 hours24 hoursAll systems
68 hours16 hoursAll systems + multi-band
62 hours—All systems with music
18 hours—
More comparisons
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2D Dimension Schematics
- Garmin Fenix 8 51mm AMOLED 51mm × ≈58.5mm (est.) · 14.7mm thick
- Garmin Instinct E 45mm 45mm × ≈51.5mm (est.) · 14.2mm thick
3D preview
Fenix 8 51mm AMOLED vs Instinct E 45mm on a wrist
Specifications
The short version
7 key specs| Spec | GarminFenix 8 51mm AMOLED | GarminInstinct E 45mm |
|---|---|---|
| Case Width | 51mm | 45mm |
| Thickness | 14.7mm | 14.2mm |
| Weight | 102g | 48g |
| Shape | Circular | Circular |
| Display type | AMOLED | Monochrome, sunlight-visible, transflective memory-in-pixel (MIP) |
| Battery life | Smartwatch: Up to 29 days (13 days always-on) Battery Saver Watch Mode: Up to 41 days GPS Only: Up to 84 hours (65 hours always-on) All Satellite Systems: Up to 68 hours (54 hours always-on) All Satellite Systems + Multi-band: Up to 62 hours (49 hours always-on)* All Satellite Systems + Music: Up to 18 hours Max Battery GPS: Up to 145 hours Expedition GPS: Up to 31 days *Assuming typical use with SatIQ technology | Smartwatch: Up to 16 days Battery Saver Watch Mode: Up to 40 days GPS: Up to 24 hours All Satellite Systems:16 hours Max Battery GPS Mode: Up to 50 hours Expedition GPS Activity: Up to 20 days |
| Released | 2024 | 2025 |
Where the specifications differ
26 differences| Spec | Garmin Fenix 8 51mm AMOLED | Garmin Instinct E 45mm |
|---|---|---|
| General | ||
| Battery life | Smartwatch: Up to 29 days (13 days always-on) Battery Saver Watch Mode: Up to 41 days GPS Only: Up to 84 hours (65 hours always-on) All Satellite Systems: Up to 68 hours (54 hours always-on) All Satellite Systems + Multi-band: Up to 62 hours (49 hours always-on)* All Satellite Systems + Music: Up to 18 hours Max Battery GPS: Up to 145 hours Expedition GPS: Up to 31 days *Assuming typical use with SatIQ technology | Smartwatch: Up to 16 days Battery Saver Watch Mode: Up to 40 days GPS: Up to 24 hours All Satellite Systems:16 hours Max Battery GPS Mode: Up to 50 hours Expedition GPS Activity: Up to 20 days |
| Display Size | 1.4” (35.56 mm) diameter | custom, two-window design; 0.9” x 0.9” (23 x 23 mm) |
| Case material | fiber-reinforced polymer with metal rear cover | fiber-reinforced polymer |
| Lens Material | Corning® Gorilla® Glass or sapphire crystal | Chemically Strengthened Glass |
| Bezel Material | stainless steel or titanium | fiber-reinforced polymer |
| Memory/History | 32 GB | 128 MB |
| Display resolution | 454 x 454 pixels | 176 x 176 pixels |
| QuickFit® watch band compatible | included (26 mm) | yes (22 mm) |
| Product Info | ||
| Main SKU | 010-02905-10 | 010-02933-00 |
| Product ID | 1228171 | 1315817 |
| Product Name | fēnix® 8 – 51 mm, AMOLED | Instinct® E – 45 mm |
| Release Date | 8/27/2024 | 1/6/2025 |
| Product Variation | Sapphire, Titanium with Spark Orange/Graphite Silicone Band | Black with Charcoal Band |
| Running Features | ||
| Ground contact time and balance | yes (GCT balance with accessory) | yes (but not balance) |
| What You'll Love | ||
| Display type | AMOLED | Monochrome, sunlight-visible, transflective memory-in-pixel (MIP) |
| Battery life (smartwatch mode) | Up to 29 days (13 days always-on) | Up to 16 days |
| Activity Profiles | ||
| Gym | Strength, HIIT, Cardio, Elliptical Training, Stair Stepping, Floor Climbing, Indoor Rowing, Jump Roping | Strength, HIIT, Cardio, Elliptical Training, Stair Stepping, Floor Climbing, Indoor Rowing |
| Wellness | Walking, Indoor Walking, Pilates, Yoga | Walking, Pilates, Yoga |
| On the Water | Stand Up Paddleboarding, Rowing, Kayaking, Surfing, Kiteboarding, Windsurfing, Fishing, Boating, Sailing, Water Skiing, Wakeboarding, Wakesurfing, Tubing, Snorkeling, Whitewater | Stand Up Paddleboarding, Rowing, Kayaking, Fishing, Boating, Whitewater |
| Snow & winter | Skiing, Snowboarding, Backcountry Snowboarding, XC Classic Skiing, XC Skate Skiing, Backcountry Skiing, Ice Skating, Snowshoeing | Skiing, Snowboarding, XC Classic Skiing, XC Skate Skiing, Ice Skating, Snowshoeing |
| Outdoor running | Running, Outdoor Track Running, Trail Running, Ultra Running, Obstacle Racing | Running, Outdoor Track Running, Trail Running |
| Outdoor recreation | Hiking, Rucking, Indoor Climbing, Bouldering, Climbing, Hunting, Horseback Riding, Golfing, Disc Golf, Archery | Hiking, Climbing, Hunting, Horseback Riding, Archery |
| Other activity profiles | Inline Skating | Tactical |
| Outdoor Recreation | ||
| Area calculation | yes (via Connect IQ™) | Yes |
| Daily Smart Features | ||
| Connectivity | Bluetooth®, ANT+®, Wi-Fi® | Bluetooth®, ANT+® |
| Training, Planning and Analysis Features | ||
| Respiration rate (during exercise) | yes (with compatible accessory) | Yoga and Breathwork only |
The other 168 specifications both list are identical.
Full Garmin Fenix 8 51mm AMOLED specifications →Full Garmin Instinct E 45mm specifications →