Garmin Forerunner® 45S vs Garmin Instinct® E – 40 mmSize, Specs & Wrist Fit Compared
Switch or add watches
Garmin
Forerunner® 45S (010-02156-00)
Garmin
Instinct® E – 40 mm (010-02932-00)
The Garmin Instinct® E – 40 mm wears larger than the Garmin Forerunner® 45S (40mm vs 39.5mm case), giving it more wrist presence — and needing a wider wrist to sit cleanly.
The Garmin Forerunner® 45S is the slimmer of the two (11.4mm vs 13.6mm), so it slides under a cuff more easily.
On the wrist the Garmin Forerunner® 45S feels lighter (32g vs 41g, case only).
Specification Comparison
| Spec | GarminForerunner® 45S | GarminInstinct® E – 40 mm |
|---|---|---|
| Case Width | 39.5mm | 40mm |
| Thickness | 11.4mm | 13.6mm |
| Weight | 32g | 41g |
| Shape | Circular | Circular |
| GPS | Yes | Yes |
| Battery Life | Smartwatch Mode: Up to 7 days GPS mode: Up to 13 hours | 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 |
| Display | Sunlight-visible, transflective memory-in-pixel (MIP) | Monochrome, sunlight-visible, transflective memory-in-pixel (MIP) |
| Released | 2019 | 2025 |
Full Specification Comparison
200 specs| Spec | Garmin Forerunner® 45S | Garmin Instinct® E – 40 mm |
|---|---|---|
| Overview | ||
| Family | Garmin | Garmin |
| General | ||
| Battery life | Smartwatch Mode: Up to 7 days GPS mode: Up to 13 hours | 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 |
| Display Size | 1.04" (26.3 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 |
| Memory/History | 80 hours of activity data | 128 MB |
| Strap material | silicone | silicone |
| Charging method | Garmin proprietary plug charger | Garmin proprietary plug charger |
| Display resolution | 208 x 208 pixels | 166 x 166 pixels (active area) |
| Battery type | — | Lithium ion |
| Case material | — | fiber-reinforced polymer |
| Bezel Material | — | fiber-reinforced polymer |
| QuickFit® watch band compatible | — | yes (20 mm) |
| Sensors | ||
| GPS | Yes | Yes |
| GLONASS | Yes | Yes |
| Galileo | Yes | Yes |
| Accelerometer | Yes | Yes |
| Garmin Elevate™ wrist heart rate monitor | Yes | Yes |
| Compass | — | Yes |
| Thermometer | — | Yes |
| Barometric altimeter | — | Yes |
| Pulse Ox Blood Oxygen Saturation Monitor | — | Yes |
| Product Info | ||
| Main SKU | 010-02156-00 | 010-02932-00 |
| Product ID | 682416 | 1314137 |
| Product Name | Forerunner® 45S | Instinct® E – 40 mm |
| Release Date | 4/30/2019 | 1/6/2025 |
| Product Variation | White | 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 |
| Automatic daylight saving time | Yes | Yes |
| Sunrise/sunset times | — | Yes |
| Cycling Features | ||
| Speed and cadence sensor support (w/sensor) | Yes | Yes |
| Alerts (triggers alarm when you reach goals including time, distance, heart rate or calories) | Yes | Yes |
| Courses | — | Yes |
| Race an activity | — | Yes |
| Compatible with Varia™ lights | — | Yes |
| Running Features | ||
| Run workouts | Yes | Yes |
| Foot pod capable | Yes | Yes |
| GPS-based distance, time and pace | Yes | Yes |
| Cadence (provides real-time number of steps per minute) | Yes | Yes |
| Race predictor | — | Yes |
| Running dynamics | — | Yes |
| Trail run auto climb | — | Yes |
| Run/Walk/Stand detection | — | Yes |
| Stride length (real time) | — | Yes |
| Vertical oscillation and ratio | — | Yes |
| Ground contact time and balance | — | yes (but not balance) |
| What You'll Love | ||
| Display type | Sunlight-visible, transflective memory-in-pixel (MIP) | Monochrome, sunlight-visible, transflective memory-in-pixel (MIP) |
| Water rating | 5 ATM | 10 ATM |
| Battery life (smartwatch mode) | Up to 7 days | Up to 14 days |
| Pulse Ox blood oxygen | — | Yes |
| Sleep score and insights | — | Yes |
| Activity Profiles | ||
| Gym | Cardio, Elliptical Training, Stair Stepping | Strength, HIIT, Cardio, Elliptical Training, Stair Stepping, Floor Climbing, Indoor Rowing |
| Cycling | Biking, Indoor Biking | Biking, Road Biking, Mountain Biking, Gravel Biking, Bike Commuting, Bike Touring, eBiking, eMountain Biking, Indoor Biking, Cyclocross, BMX |
| Wellness | Yoga | Walking, Pilates, Yoga |
| Indoor running | Treadmill Running, Indoor Track Running | Treadmill Running, Indoor Track Running, Virtual Running |
| Outdoor running | Running | Running, Outdoor Track Running, Trail Running |
| Swim | — | Pool Swimming, Open Water Swimming |
| 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 |
| Racket sports | — | Tennis, Pickleball, Badminton, Squash, Table Tennis, Padel, Platform Tennis, Racquetball |
| Snow & winter | — | Skiing, Snowboarding, XC Classic Skiing, XC Skate Skiing, Ice Skating, Snowshoeing |
| Outdoor recreation | — | Hiking, Climbing, Hunting, Horseback Riding, Archery |
| Other activity profiles | — | Tactical |
| Daily Smart Features | ||
| Calendar | Yes | Yes |
| Connectivity | Yes | Bluetooth®, ANT+® |
| Find My Phone | Yes | Yes |
| Find My Watch | Yes | Yes |
| Weather forecasts | Yes | Yes |
| Smart Notifications | Yes | Yes |
| Smartphone compatibility | iPhone®, Android™ | iPhone®, Android™ |
| Controls smartphone music | Yes | Yes |
| Pairs with Garmin Connect™ Mobile | Yes | Yes |
| Connect IQ™ (downloadable watch faces, data fields and apps) | yes (watch faces only) | Yes |
| Passcode | — | Yes |
| Garmin Share | — | Yes |
| VIRB® Remote | — | Yes |
| Morning report | — | Yes |
| On-device Connect IQ™ Store | — | Yes |
| Battery saver (customizable low power watch) | — | Yes |
| Realtime settings sync with Garmin Connect™ mobile | — | Yes |
| Text response/reject phone call with text (Android™ only) | — | Yes |
| Activity Tracking Features | ||
| TrueUp™ | Yes | Yes |
| Move IQ™ | Yes | Yes |
| Step counter | Yes | Yes |
| Calories burned | Yes | Yes |
| Distance traveled | Yes | Yes |
| Intensity minutes | Yes | Yes |
| 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 |
| Floors climbed | — | Yes |
| Automatic rep counting | — | Yes |
| Garmin Connect™ Challenges app | — | yes (optional Connect IQ app) |
| Health & Wellness Monitoring | ||
| Sleep | yes (advanced) | yes (advanced) |
| Fitness age | yes (in app) | Yes |
| All-day stress | Yes | Yes |
| Resting heart rate | 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 |
| Hydration | — | yes (in Garmin Connect™ and optional Connect IQ™ widget) |
| Breathwork | — | Yes |
| Nap detection | — | Yes |
| Women's health | — | yes (in Garmin Connect™ and optional Connect IQ™ widget) |
| Health snapshot | — | Yes |
| Respiration rate | — | Yes |
| Breathing variations | — | Yes |
| Relaxation reminders | — | Yes |
| Safety and Tracking Features | ||
| Assistance | yes (smartphone required) | Yes |
| Live Event Sharing | Android™ Only | Yes |
| Incident Detection during select activities | yes (smartphone required) | Yes |
| Incident detection alert on phone for wearables | — | Yes |
| Training, Planning and Analysis Features | ||
| HR zones | Yes | Yes |
| HR alerts | Yes | Yes |
| Manual lap | Yes | Yes |
| HR calories | Yes | Yes |
| Voice alerts | Yes | Yes |
| Physio TrueUp | Yes | Yes |
| VO2 Max (Run) | Yes | Yes |
| Advanced workouts | Yes | Yes |
| Interval training | Yes | Yes |
| GPS speed and distance | 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 |
| Customizable activity profiles | Yes | Yes |
| Auto Pause® automatic timer halt | Yes | Yes |
| Auto Lap® interval tracking feature | Yes | Yes |
| HR broadcast (broadcasts HR data over ANT+® to paired devices) | Yes | Yes |
| % HRR | — | Yes |
| % HR max | — | Yes |
| Shortcuts | — | Yes |
| HRV status | — | Yes |
| Rest timer | — | Yes |
| Auto max HR | — | Yes |
| Auto scroll | — | Yes |
| Finish time | — | Yes |
| Custom alerts | — | Yes |
| Recovery time | — | Yes |
| Course guidance | — | Yes |
| Training effect | — | Yes |
| Virtual Partner | — | Yes |
| Workout benefit | — | Yes |
| Race an Activity | — | Yes |
| VO2 Max (Trail Run) | — | Yes |
| Configurable lap alerts | — | Yes |
| Training effect (anaerobic) | — | Yes |
| HRM running pace and distance | — | Yes |
| Heat and altitude acclimation | — | Yes |
| Respiration rate (during exercise) | — | Yoga and Breathwork only |
| Primary benefit (Training Effect labels) | — | Yes |
| Power Modes - customizable in-activity battery settings | — | Yes |
| Swimming Features | ||
| Pool swim workouts | — | Yes |
| Time and distance alerts | — | Yes |
| Auto rest (pool swim only) | — | Yes |
| Drill logging (pool swim only) | — | Yes |
| Countdown start (pool swim only) | — | Yes |
| Underwater wrist-based heart rate | — | Yes |
| "Repeat on" rest timer (pool swim only) | — | Yes |
| Basic rest timer (up from 0) (pool swim only) | — | Yes |
| Stroke type detection (freestyle, backstroke, breaststroke, butterfly) (pool swim only) | — | Yes |
| Pool swim metrics (lengths, distance, pace, stroke count, swim efficiency (SWOLF), calories) | — | Yes |
| Open-water swim metrics (distance, pace, stroke count/rate, stroke distance, swim efficiency (SWOLF), calories) | — | Yes |
| Tactical Features | ||
| XERO™ Locations | — | Yes |
| Dual grid coordinates | — | Yes |
| Outdoor Recreation | ||
| Tides | — | Yes |
| TracBack® | — | Yes |
| Sight 'N Go | — | Yes |
| Tide glance | — | Yes |
| Back to start | — | Yes |
| UltraTrac mode | — | Yes |
| Vertical speed | — | Yes |
| GPS coordinates | — | Yes |
| Reference point | — | Yes |
| Area calculation | — | Yes |
| Elevation profile | — | Yes |
| Projected waypoint | — | Yes |
| Total ascent/descent | — | Yes |
| Future elevation plot | — | Yes |
| Distance to destination | — | Yes |
| Expedition GPS Activity | — | Yes |
| Sun and moon information | — | Yes |
| Point-to-point navigation | — | Yes |
| Bread crumb trail in real time | — | Yes |
| Barometric trend indicator with Storm Alert | — | Yes |
| Workout and Training Plans | ||
| HIIT workouts | — | Yes |
| Yoga workouts | — | Yes |
| Cardio workouts | — | Yes |
| Pilates workouts | — | Yes |
| Strength workouts | — | Yes |
| Garmin Running Coach Experts | — | Yes |
| Garmin Coach - Prebuilt Cycling Plans | — | Yes |
| Daily Suggested Workout - Cycling (Pace and Heart Rate Based) | — | Yes |
| Daily Suggested Workout - Running (Pace and Heart Rate Based) | — | Yes |
| Kid Activity Tracking Features | ||
| Toe-to-Toe™ Challenges app | — | yes (optional Connect IQ Toe-to-Toe™ Challenges app) |
Wrist Fit
Garmin Forerunner® 45S
Sits best on wrists ~42–56mm wide (≈ 11.2–15.0cm circumference).
Garmin Instinct® E – 40 mm
Sits best on wrists ~42–57mm wide (≈ 11.2–15.2cm circumference).
2D Dimension Schematics
Accurate scale drawings based on case dimensions. Drag to pan, Ctrl+scroll to zoom. Works for every watch regardless of photo availability.
Loading schematics…
Frequently Asked Questions
Is the Garmin Forerunner® 45S bigger than the Garmin Instinct® E – 40 mm?
The Garmin Instinct® E – 40 mm is bigger — 40mm vs 39.5mm case width.
Which fits a smaller wrist better, the Garmin Forerunner® 45S or the Garmin Instinct® E – 40 mm?
The Garmin Forerunner® 45S suits wrists around 42–56mm wide, and the Garmin Instinct® E – 40 mm around 42–57mm. The one with the smaller lower bound is the safer pick for a small wrist.
Can I see the Garmin Forerunner® 45S and Garmin Instinct® E – 40 mm 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.
Related Comparisons
Garmin Forerunner® 45S vs Garmin Instinct® 2S SolarGarmin Forerunner® 45S vs Garmin Instinct® 2S - Standard EditionGarmin Forerunner® 45S vs Garmin Instinct® 2S - Camo EditionGarmin Instinct® E – 40 mm vs Garmin Instinct® 2S SolarGarmin Instinct® E – 40 mm vs Garmin Instinct® 2S - Camo EditionGarmin Instinct® E – 40 mm vs Garmin Instinct® 2S - Standard EditionGarmin Instinct® E – 40 mm vs Garmin Vivomove Sport