Garmin Forerunner 165 vs Instinct E 40mm
Size, specs & wrist fit compared
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Which one fits you
On wrists narrower than about 45mm, the Instinct E 40mm is the safer pick — it stays proportionate down to roughly 42mm, where the Forerunner 165 starts to hang over the edge. Above 45mm both sit cleanly, and the Forerunner 165 gives you more presence.
The Forerunner 165 wears larger than the Instinct E 40mm (43mm vs 40mm case), giving it more wrist presence — and needing a wider wrist to sit cleanly.
The Forerunner 165 is the slimmer of the two (11.6mm vs 13.6mm), so it slides under a cuff more easily.
On the wrist the Forerunner 165 feels lighter (39g vs 41g, case only).
Among the 318 43mm watches we hold thickness for, the Forerunner 165 is thinner than 86%, so it wears flatter than its width suggests.
Among the 539 40mm watches we hold thickness for, the Instinct E 40mm is thicker than 98% — it will sit high even though the case width reads modest.
The Forerunner 165 is 3mm wider, 3mm longer, 2mm thinner and 2g lighter than the Instinct E 40mm. Both are circular.
Forerunner® 165
Instinct® E – 40 mm
Switch or add watches
Garmin
Forerunner® 165
Garmin
Instinct® E – 40 mm
Watch Fit Tool
For sports watches, lug-to-lug (L2L) is what matters most — it decides whether a watch overhangs your wrist. Bulky is fine; overhang is not.
Measure at the point where you wear your watch — typically just below the wrist bone.
Flat width — lay your arm on a table, palm facing up, and measure straight across the top of your wrist with a ruler. Bone to bone; do not follow the curve down the sides.
Around — wrap a tape measure snugly round the wrist. No tape? Wrap a strip of paper, mark the overlap and hold the strip against a ruler.
Width ≠ circumference. They are different numbers — around 170mm is about 64mm across — so set the toggle to whichever one you actually measured before you type it in.
Garmin Forerunner® 165
Case 43.0mm · Lug-to-lug 43.0mm · Thickness 11.6mm · 39g
Balanced Fit
43mm on a 55mm wrist
Comfortably inside the edges of your wrist, and it seats and sits low enough to wear without thinking about it.
On a 55mm wrist the sweet spot is 47–53mm lug to lug. This one is 43mm, so you could go bigger.
Measure where you wear it, just below the wrist bone. Either of these works — the tool converts between them.
- 1. Flat width — arm flat on a table, palm up. Measure straight across the top of the wrist, bone to bone, ignoring the curve down the sides.
- 2. Around — a tape, or a strip of paper marked and held against a ruler, snug the whole way round.
Leather: Attaches at the lugs, so the case back rests on your skin. Thins and softens with wear. Typical figures, not this model’s own.
Show the measurementsHide the measurements
- Across the wrist6.0mm spare each side
Comfortable, with visible skin either side.
- Off the wrist11.6mm off the skin
Normal sports-watch height for a wrist this size. (11.6mm case, back against the skin)
- How it seats~4.4mm under the rim
Seats well, with the case back following most of the wrist.
- Weight on the wrist39g
Light enough to forget you have it on. (0.7g per mm of wrist)
Garmin Instinct® E – 40 mm
Case 40.0mm · Lug-to-lug 40.0mm · Thickness 13.6mm · 41g
Balanced Fit
40mm on a 55mm wrist
Across the wrist it works — 7.5mm spare each side — but a tall watch on this wrist. Fine over a sleeve, awkward under one.
On a 55mm wrist the sweet spot is 47–53mm lug to lug. This one is 40mm, so you could go bigger.
Measure where you wear it, just below the wrist bone. Either of these works — the tool converts between them.
- 1. Flat width — arm flat on a table, palm up. Measure straight across the top of the wrist, bone to bone, ignoring the curve down the sides.
- 2. Around — a tape, or a strip of paper marked and held against a ruler, snug the whole way round.
Leather: Attaches at the lugs, so the case back rests on your skin. Thins and softens with wear. Typical figures, not this model’s own.
Show the measurementsHide the measurements
- Across the wrist7.5mm spare each side
Comfortable, with visible skin either side.
- Off the wrist13.6mm off the skin
A tall watch on this wrist. Fine over a sleeve, awkward under one. (13.6mm case, back against the skin)
- How it seats~3.4mm under the rim
Seats well, with the case back following most of the wrist.
- Weight on the wrist41g
Light enough to forget you have it on. (0.7g per mm of wrist)
2D Dimension Schematics
Every case drawn to scale on a shared centre — from above, and in profile against the wrist.
- Garmin Forerunner® 16543mm · 11.6mm thick
- Garmin Instinct® E – 40 mm40mm · 13.6mm thick
3D preview
Forerunner® 165 vs Instinct® E – 40 mm on a wrist
Sized to your own wrist, turned any way you like.
Shapes are built from published measurements, not manufacturer 3D models — accurate proportions, generic dial.
Battery life compared
Furthest apart in Smartwatch mode, where the Instinct E 40mm lasts 1.3× as long as the Forerunner 165 (14 days against 11 days).
Forerunner 165Instinct E 40mm
Battery Saver
—35 daysBattery Saver Smartwatch
20 days—Expedition GPS Activity
—17 daysSmartwatch
11 days14 daysMax Battery GPS
—43 hoursGPS
—21 hoursGPS-Only GNSS
19 hours—All-Systems GNSS
17 hours—All Satellite Systems
—14 hours
Specifications
The short version
7 key specs| Spec | GarminForerunner® 165 | GarminInstinct® E – 40 mm |
|---|---|---|
| Case Width | 43mm | 40mm |
| Thickness | 11.6mm | 13.6mm |
| Weight | 39g | 41g |
| Shape | Circular | Circular |
| Display type | AMOLED (optional always-on mode) | Monochrome, sunlight-visible, transflective memory-in-pixel (MIP) |
| Battery life | Smartwatch mode: Up to 11 days Battery Saver Smartwatch mode: Up to 20 days GPS-Only GNSS mode: Up to 19 hours All-Systems GNSS mode: Up to 17 hours See Details | Smartwatch: Up to 14 days Battery Saver Watch Mode: Up to 35 days GPS: Up to 21 hours All Satellite Systems: 14 hours Max Battery GPS Mode: Up to 43 hours Expedition GPS Activity: Up to 17 days |
| Released | 2024 | 2025 |
Every specification
219 specs| Spec | Garmin Forerunner® 165 | Garmin Instinct® E – 40 mm |
|---|---|---|
| Overview | ||
| Family | Garmin | Garmin |
| General | ||
| Battery life | Smartwatch mode: Up to 11 days Battery Saver Smartwatch mode: Up to 20 days GPS-Only GNSS mode: Up to 19 hours All-Systems GNSS mode: Up to 17 hours See Details | Smartwatch: Up to 14 days Battery Saver Watch Mode: Up to 35 days GPS: Up to 21 hours All Satellite Systems: 14 hours Max Battery GPS Mode: Up to 43 hours Expedition GPS Activity: Up to 17 days |
| Battery type | Lithium ion | Lithium ion |
| Display Size | 1.2" (30.4 mm) diameter | custom, two-window design; 0.86” x 0.86” (22 x 22 mm) |
| Color display | Yes | — |
| Lens Material | chemically strengthened glass | Chemically Strengthened Glass |
| Bezel Material | fiber-reinforced polymer | fiber-reinforced polymer |
| Memory/History | 4 GB | 128 MB |
| Strap material | silicone | silicone |
| Charging method | Garmin proprietary plug charger | Garmin proprietary plug charger |
| Large font option | Yes | — |
| Display resolution | 390 x 390 pixels | 166 x 166 pixels (active area) |
| Quick Release bands | yes (20 mm, Industry standard) | — |
| Case material | — | fiber-reinforced polymer |
| QuickFit® watch band compatible | — | yes (20 mm) |
| Sensors | ||
| GPS | Yes | Yes |
| Compass | Yes | Yes |
| GLONASS | Yes | Yes |
| Galileo | Yes | Yes |
| Thermometer | Yes | Yes |
| Accelerometer | Yes | Yes |
| Ambient light sensor | Yes | — |
| Barometric altimeter | Yes | Yes |
| Pulse Ox Blood Oxygen Saturation Monitor | Yes | Yes |
| Garmin Elevate™ wrist heart rate monitor | Yes | Yes |
| Product Info | ||
| Main SKU | 010-02863-20 | 010-02932-00 |
| Product ID | 1055469 | 1314137 |
| Product Name | Forerunner® 165 | Instinct® E – 40 mm |
| Release Date | 2/20/2024 | 1/6/2025 |
| Product Variation | Black/Slate Gray | Black with Charcoal Band |
| Clock Features | ||
| Timer | Yes | Yes |
| Stopwatch | Yes | Yes |
| Time/date | Yes | Yes |
| Alarm clock | Yes | Yes |
| GPS Time Sync | Yes | Yes |
| Sunrise/sunset times | Yes | Yes |
| Automatic daylight saving time | Yes | Yes |
| Cycling Features | ||
| Courses | Yes | Yes |
| Compatible with Varia™ lights | Yes | Yes |
| Compatible with Varia headlight camera | Yes | — |
| Speed and cadence sensor support (w/sensor) | Yes | Yes |
| Compatible with Varia™ radar (rear-facing radar) | Yes | — |
| Alerts (triggers alarm when you reach goals including time, distance, heart rate or calories) | Yes | Yes |
| Race an activity | — | Yes |
| Running Features | ||
| Run workouts | Yes | Yes |
| Running power | Yes | — |
| Race predictor | Yes | Yes |
| Foot pod capable | Yes | Yes |
| Running dynamics | Yes | Yes |
| Run/Walk/Stand detection | Yes | Yes |
| Stride length (real time) | Yes | Yes |
| PacePro™ Pacing Strategies | Yes | — |
| Vertical oscillation and ratio | Yes | Yes |
| Ground contact time and balance | yes (but not balance) | yes (but not balance) |
| GPS-based distance, time and pace | Yes | Yes |
| Course- and weather-specific race predictor | Yes | — |
| Cadence (provides real-time number of steps per minute) | Yes | Yes |
| Trail run auto climb | — | Yes |
| What You'll Love | ||
| Touchscreen | Yes | — |
| Display type | AMOLED (optional always-on mode) | Monochrome, sunlight-visible, transflective memory-in-pixel (MIP) |
| Water rating | 5 ATM | 10 ATM |
| Garmin Pay™ | Yes | — |
| Pulse Ox blood oxygen | yes (spot-check, during sleep, all day) | Yes |
| Sleep score and insights | Yes | Yes |
| Battery life (smartwatch mode) | Up to 11 days | Up to 14 days |
| Activity Profiles | ||
| Gym | Strength, HIIT, Cardio, Elliptical Training, Stair Stepping, Floor Climbing | Strength, HIIT, Cardio, Elliptical Training, Stair Stepping, Floor Climbing, Indoor Rowing |
| Swim | Pool Swimming, Open Water Swimming | Pool Swimming, Open Water Swimming |
| Cycling | Biking, Indoor Biking | Biking, Road Biking, Mountain Biking, Gravel Biking, Bike Commuting, Bike Touring, eBiking, eMountain Biking, Indoor Biking, Cyclocross, BMX |
| Wellness | Walking, Pilates, Yoga, Indoor Walking | Walking, Pilates, Yoga |
| Racket sports | Tennis, Pickleball, Padel | Tennis, Pickleball, Badminton, Squash, Table Tennis, Padel, Platform Tennis, Racquetball |
| Indoor running | Treadmill Running, Indoor Track Running, Virtual Running | Treadmill Running, Indoor Track Running, Virtual Running |
| Outdoor running | Running, Outdoor Track Running, Trail Running, Ultra Running | Running, Outdoor Track Running, Trail Running |
| Outdoor recreation | Hiking | Hiking, Climbing, Hunting, Horseback Riding, Archery |
| Team sports | — | Basketball, Volleyball, Field Hockey, Ice Hockey, Football/Soccer, American Football, Lacrosse, Rugby, Ultimate Disc, Cricket, Softball, Baseball |
| On the Water | — | Stand Up Paddleboarding, Rowing, Kayaking, Fishing, Boating, Whitewater |
| Snow & winter | — | Skiing, Snowboarding, XC Classic Skiing, XC Skate Skiing, Ice Skating, Snowshoeing |
| Other activity profiles | — | Tactical |
| Swimming Features | ||
| Time and distance alerts | Yes | Yes |
| Auto rest (pool swim only) | Yes | Yes |
| Drill logging (pool swim only) | Yes | Yes |
| Countdown start (pool swim only) | Yes | Yes |
| Underwater wrist-based heart rate | Yes | Yes |
| "Repeat on" rest timer (pool swim only) | Yes | Yes |
| Basic rest timer (up from 0) (pool swim only) | Yes | Yes |
| Stroke type detection (freestyle, backstroke, breaststroke, butterfly) (pool swim only) | Yes | Yes |
| Pool swim metrics (lengths, distance, pace, stroke count, swim efficiency (SWOLF), calories) | Yes | Yes |
| Open-water swim metrics (distance, pace, stroke count/rate, stroke distance, swim efficiency (SWOLF), calories) | Yes | Yes |
| Pool swim workouts | — | Yes |
| Outdoor Recreation | ||
| Auto rest | Yes | — |
| TracBack® | Yes | Yes |
| Back to start | Yes | Yes |
| Fish forecast | yes (via Connect IQ™) | — |
| UltraTrac mode | Yes | Yes |
| Area calculation | yes (via Connect IQ™) | Yes |
| Elevation profile | Yes | Yes |
| Total ascent/descent | Yes | Yes |
| Future elevation plot | Yes | Yes |
| Distance to destination | Yes | Yes |
| Sun and moon information | yes (via Connect IQ™) | Yes |
| Point-to-point navigation | Yes | Yes |
| Rest Timer (Ultra Run only) | Yes | — |
| Bread crumb trail in real time | Yes | Yes |
| Tides | — | Yes |
| Sight 'N Go | — | Yes |
| Tide glance | — | Yes |
| Vertical speed | — | Yes |
| GPS coordinates | — | Yes |
| Reference point | — | Yes |
| Projected waypoint | — | Yes |
| Expedition GPS Activity | — | Yes |
| Barometric trend indicator with Storm Alert | — | Yes |
| Daily Smart Features | ||
| Calendar | Yes | Yes |
| Passcode | Yes | Yes |
| Connectivity | Bluetooth®, ANT+® | Bluetooth®, ANT+® |
| Garmin Share | Yes | Yes |
| Find My Phone | Yes | Yes |
| Find My Watch | Yes | Yes |
| Morning report | Yes | Yes |
| Red shift mode | Yes | — |
| Weather forecasts | Yes | Yes |
| Smart Notifications | Yes | Yes |
| Smartphone compatibility | iPhone®, Android™ | iPhone®, Android™ |
| Controls smartphone music | Yes | Yes |
| On-device Connect IQ™ Store | Yes | Yes |
| Find My Phone during GPS activity | Yes | — |
| Pairs with Garmin Connect™ Mobile | Yes | Yes |
| Compatible with Garmin Messenger app | Yes | — |
| Battery saver (customizable low power watch) | Yes | Yes |
| Realtime settings sync with Garmin Connect™ mobile | Yes | Yes |
| View images from notifications on watch (Android™ only) | Yes | — |
| Text response/reject phone call with text (Android™ only) | Yes | Yes |
| Connect IQ™ (downloadable watch faces, data fields and apps) | Yes | Yes |
| VIRB® Remote | — | Yes |
| Activity Tracking Features | ||
| TrueUp™ | Yes | Yes |
| Move IQ™ | Yes | Yes |
| Step counter | Yes | Yes |
| Floors climbed | Yes | Yes |
| Calories burned | Yes | Yes |
| Distance traveled | Yes | Yes |
| Intensity minutes | Yes | Yes |
| Automatic rep counting | Yes | Yes |
| Garmin Connect™ Challenges app | yes (optional Connect IQ app) | yes (optional Connect IQ app) |
| Move alerts (displays on device after a period of inactivity) | Yes | Yes |
| Auto goal (learns your activity level and assigns a daily step goal) | Yes | Yes |
| Workout and Training Plans | ||
| HIIT workouts | Yes | Yes |
| Yoga workouts | Yes | Yes |
| Cardio workouts | Yes | Yes |
| Pilates workouts | Yes | Yes |
| Strength workouts | Yes | Yes |
| Garmin Running Coach | yes (no strength add-on) | — |
| Garmin Running Coach Experts | Yes | Yes |
| Garmin Coach - Prebuilt Cycling Plans | Yes | Yes |
| Daily Suggested Workout - Running (Pace and Heart Rate Based) | Yes | Yes |
| Daily Suggested Workout - Cycling (Pace and Heart Rate Based) | — | Yes |
| Health & Wellness Monitoring | ||
| Sleep | yes (advanced) | yes (advanced) |
| Hydration | yes (in Garmin Connect™ and optional Connect IQ™ widget) | yes (in Garmin Connect™ and optional Connect IQ™ widget) |
| Breathwork | Yes | Yes |
| Fitness age | Yes | Yes |
| Nap detection | Yes | Yes |
| All-day stress | Yes | Yes |
| Women's health | yes (in Garmin Connect™ and optional Connect IQ™ widget) | yes (in Garmin Connect™ and optional Connect IQ™ widget) |
| Health snapshot | Yes | Yes |
| Respiration rate | Yes | Yes |
| Resting heart rate | Yes | Yes |
| Breathing variations | Yes | Yes |
| Relaxation reminders | Yes | Yes |
| Abnormal heart rate alerts | yes (high and low) | yes (high and low) |
| Relaxation breathing timer | Yes | Yes |
| Body Battery™ energy monitor | Yes | Yes |
| Wrist-based heart rate (constant, every second) | Yes | Yes |
| Safety and Tracking Features | ||
| Assistance | Yes | Yes |
| Live Event Sharing | Android™ Only | Yes |
| Incident Detection during select activities | Yes | Yes |
| Incident detection alert on phone for wearables | Yes | Yes |
| Kid Activity Tracking Features | ||
| Toe-to-Toe™ Challenges app | yes (optional Connect IQ Toe-to-Toe™ Challenges app) | yes (optional Connect IQ Toe-to-Toe™ Challenges app) |
| Training, Planning and Analysis Features | ||
| % HRR | Yes | Yes |
| % HR max | Yes | Yes |
| HR zones | Yes | Yes |
| HR alerts | Yes | Yes |
| HRV status | Yes | Yes |
| Manual lap | Yes | Yes |
| Rest timer | Yes | Yes |
| Auto max HR | Yes | Yes |
| Finish time | Yes | Yes |
| HR calories | Yes | Yes |
| Voice alerts | Yes | Yes |
| Physio TrueUp | Yes | Yes |
| Recovery time | Yes | Yes |
| VO2 Max (Run) | Yes | Yes |
| Course guidance | Yes | Yes |
| Training effect | Yes | Yes |
| Advanced workouts | Yes | Yes |
| Interval training | Yes | Yes |
| Race glance/widget | Yes | — |
| VO2 Max (Trail Run) | Yes | Yes |
| GPS speed and distance | Yes | Yes |
| Configurable lap alerts | Yes | Yes |
| Customizable data pages | Yes | Yes |
| Touch and/or button lock | Yes | Yes |
| Activity history on watch | Yes | Yes |
| Downloadable training plans | Yes | Yes |
| Training effect (anaerobic) | Yes | Yes |
| HRM running pace and distance | Yes | Yes |
| Customizable activity profiles | Yes | Yes |
| Auto Pause® automatic timer halt | Yes | Yes |
| Respiration rate (during exercise) | Yoga and Breathwork only | Yoga and Breathwork only |
| Auto Lap® interval tracking feature | Yes | Yes |
| Primary benefit (Training Effect labels) | Yes | Yes |
| HR broadcast (broadcasts HR data over ANT+® to paired devices) | Yes | Yes |
| Shortcuts | — | Yes |
| Auto scroll | — | Yes |
| Custom alerts | — | Yes |
| Virtual Partner | — | Yes |
| Workout benefit | — | Yes |
| Race an Activity | — | Yes |
| Heat and altitude acclimation | — | Yes |
| Power Modes - customizable in-activity battery settings | — | Yes |
| Tactical Features | ||
| XERO™ Locations | — | Yes |
| Dual grid coordinates | — | Yes |
Wrist Fit
Garmin Forerunner 165
Sits best on wrists ~45–61mm wide (≈ 12.0–16.3cm circumference).
Garmin Instinct E 40mm
Sits best on wrists ~42–57mm wide (≈ 11.2–15.2cm circumference).
Frequently Asked Questions
Is the Garmin Forerunner 165 bigger than the Garmin Instinct E 40mm?
The Garmin Forerunner 165 is bigger — 43mm vs 40mm case width.
Which fits a smaller wrist better, the Garmin Forerunner 165 or the Garmin Instinct E 40mm?
The Garmin Forerunner 165 suits wrists around 45–61mm wide, and the Garmin Instinct E 40mm around 42–57mm. The one with the smaller lower bound is the safer pick for a small wrist.
Can I see the Garmin Forerunner 165 and Garmin Instinct E 40mm side by side at true scale?
Yes — the schematics and photos above show both watches at matched scale, and our fit tool overlays each on your wrist width.