Skip to content
Sale!

Garmin Forerunner 645 Specifications, Features and Price

$349.99

Date Released

November, 2017

Display

1.2 inches | 240 x 240px

Body

Fiber-reinforced polymer | 42.2 (645 Music) 41.8 (645)

Memory

Up to 500 tracks (645 Music)

Battery Life

7 days

Compatibility

Editor's Rating

Last updated on January 12, 2023 9:30 pm
Compare

Garmin Forerunner 645 is a GPS multi-sport fitness-focused smartwatch that’s well equipped to track your active life comprehensively. This watch is available in two models; the standard Forerunner 645 and Forerunner 645 Music. The later has a music storage capacity that allows you to store your favorite tracks on the watch as well as the ability to stream music from popular services such as Spotify.

The 1.2 inches transflective LCD display is very bright, not so colorful though, but can be read clearly outdoors. This watch lacks touchscreen support, but has 5 physical buttons that make navigation very easy. Its sturdily built with reinforced fiber polymer for the body, stainless steel for the bezel, silicone for the straps, while Corning Gorilla Glass 3 protects the display. It’s also rated 5ATM which makes it waterproof up to 50meters and can be worn while swimming.

Being a fitness-focused smartwatch, the Forerunner 645 is well equipped to track your heart rate, sleep, stress, VO2 Max, and many other metrics alike that makes it a comprehensive fitness tracker.

You can stay connected to all that matters to you with the Forerunner 645, you can also reply to messages with preset text response (Android only), as well as the ability to find your phone, watch and control music on your phone. There’s also NFC that enables Garmin Pay that allows you to make payment directly from this watch. The battery life is also great, you can expect about 7 days long battery life from a single charge with light usage.

READ: Garmin Forerunner 645/645 Music insightful review

Garmin Forerunner 645 Features

 Garmin Forerunner 645

SMART FEATURES

Connect IQ (Downloadable watch faces, data fields, widgets, and apps)Yes
On-device Connect IQ storeNo
Text response/reject phone calls with text (Android only)Yes
CalendarYes
WeatherYes
Real-time settings sync with Garmin Connect™ mobileNo
Battery saver - customizable low power watchNo
Controls smartphone musicYes
Plays and Control Watch Music
Find my phoneYes
Find my watchYes
Virb remoteYes

HEALTH MONITORING FEATURES

Wrist-based Heart Rate trackingYes
Daily resting heart rateYes
Abnormal heart rate alertYes
Respiration Rate (24/7)Yes
Fitness Age
Blood oxygen (SpO2) monitoringNo
Battery energy monitorNo
Stress trackingYes
Relaxation remindersYes
Relaxation breathing timerYes
Sleep monitoringYes
Advanced sleep tracking/Sleep ScoreYes
Menstrual cycle trackingYes (in Garmin Connect™ and optional Connect IQ™ widget)
Hydration trackingYes (in Garmin Connect and optional Connect IQ widget)
Health Snapshot

SAFETY AND TRACKING FEATURES

LivetrackYes
Group LivetrackNo
Live event sharingNo
Incident detection during select activitiesYes
AssistanceNo
Spectator Messaging (New)
Assistance Plus (New)

TACTICAL FEATURES

Stealth modeNo
Night vision modeNo
Dual Grid CoordinatesYes
Kill switchNo

ACTIVITY TRACKING FEATURES

Steps CounterYes
Move bar (displays on device after a period of inactivity; walk for a couple of minutes to reset it)Yes
Auto goal (learns your activity level and assigns a daily step goal)Yes
Sleep monitoring (monitors total sleep and periods of movement or restful sleep)Yes
Calories burnedYes
Floors climbedYes
Distance travelledYes
Intensity minutesYes
TrueupYes
Move IQ

Yes

GYM & FITNESS EQUIPMENT

Available gym activity profilesStrength, cardio and elliptical training, stair stepping, floor climbing, indoor rowing and yoga
Cardio workoutsYes
Strength workoutsYes
HIIT workouts
Yoga workoutsNo
Pilates workoutsNo
On-screen workout animationsNo
Automatic rep countingYes
On-screen workout muscle maps

TRAINING, PLANNING & ANALYSIS FEATURES

GPS speed and distanceYes
Customizable data pagesYes
Customizable activity profilesYes
Auto PauseYes
Interval trainingYes
Improved interval (Includes open repeats, intervals data page, rest screen and auto detection) (New)
Advanced workoutsYes
Downloadable training plansYes
Power modes - customizable in-activity battery settingsNo
Auto lapYes
Manual lapYes
Rest timer (New)
Configurable lap alertsYes
Heat and altitude acclimationNo
VO2 Max. (Run)Yes
VO2 Max. (Trail run)No
Real-Time stamina
Training status (lets you see if you're training effectively by tracking your training history and fitness level trend.)Yes
Training load (your total training load for the last 7 days calculated from estimated epoc)Yes
Training load focusNo
Training effect (aerobic)Yes
Training effect (anaerobic)Yes
Primary Benefit (training effect labels)No
Improved Recovery Time (New)
Daily Suggested Workouts (New)
Custom alertsYes
Audio promptsYes
Finish timeYes
Virtual partnerYes
Race an activityYes
Auto multisport activitiesNo
Manual multisport activitiesNo
Course guidanceYes
Garmin Live SegmentsYes
Strava Live SegmentsYes
Round-Trip course creator (running/cycling)No
Trendline Popularity RoutingNo
Touch and/or button lockYes
Hot keysNo
Auto scrollYes
Activity history on watchYes
Physio TrueupYes

HEART RATE TRACKING FEATURES

HR zonesYes
HR alertsYes
HR caloriesYes
% HR max.Yes
% HRRYes
Recovery timeYes
Auto max HRYes
Morning report (New)
Race glance/widget (New)
HRV status (New)
Training readiness (New)
HRV stress test (measures your heart rate variability while standing still, for 3 minutes, to provide you with an estimated stress level; the scale of this is 1 to 100; low scores indicate lower stress levels)No
HR broadcast (broadcasts HR data over ANT+ to paired devices)Yes
Respiration rate (during exercise)No

RUNNING FEATURES

Available run profilesRunning, treadmill running, indoor track, trail running
GPS-based distance, time and paceYes
Running dynamicsYes (with compatible accessory)
Vertical oscillation and ratio (the degree of 'bounce' in your running motion and the cost-benefit ratio with stride length)Yes (with compatible accessory)
Ground contact time and balance (shows how much time, in the running motion, your foot is on the ground rather than in flight and lets you check your running symmetry)Yes (with compatible accessory)
Stride length (real time)Yes (with compatible accessory)
Cadence (provides real-time number of steps per minute)Yes
Running power (New)
Performance condition (after running 20 minutes, compares your real-time condition to your average fitness level)Yes
Lactate threshold (through analysis of your pace and heart rate, estimates the point where your muscles start to rapidly fatigue)No
PacePro pacing strategiesNo
Run workoutsYes
Race predictorYes
Course and weather-specific race predictor (New)
Foot Pod CapableYes
Run/Walk/Stand detection

GOLF FEATURES

Preloaded with 42,000 courses worldwideNo
Yardage to F/M/B (distance to front, middle and back of green)No
Yardage to layups/doglegsNo
Measures shot distance (calculates exact yardage for shots from anywhere on course)No
Digital ScorecardNo
Custom targetsNo
Stat tracking (strokes, putts per round, greens and fairways hit)No
Garmin AutoshotNo
Full vector mapNo
Auto Courseview updatesNo
Green view with manual pin positionNo
Hazards and course targetsNo
PinpointerNo
Playslike distanceNo
Touch-targeting (touch target on display to see the distance to any point) (New)
Handicap scoringNo
Truswing compatibleNo
Round timer/odometerNo
Automatic club tracking compatible (requires accessory)No
Tournament Legal

OUTDOOR RECREATION

Available outdoor recreation profilesSkiing, snowboarding, xc skiing, stand up paddleboarding, rowing
Point-to-Point navigationYes
Bread crumb trail in real timeYes
Back to startYes
TracbacKYes
Ultratrac ModeYes
Around me modeNo
Up ahead
Elevation profileYes
Distance to destinationYes
Barometric trend indicator with storm alertNo
ClimbPro ascent plannerNo
Trail run auto climbNo
Vertical speedYes
Total ascent/descentYes
Future elevation plotNo
Preloaded Topographical mapsNo
Preloaded road and trail maps (New)
Preloaded Ski resort mapsNo
Downloadable cartography supportNo
Compatible with BasecampNo
GPS coordinatesYes
Sight 'N GONo
Area calculationNo
Hunt/fish calendarNo
Projected waypointNo
Sun and moon informationNo
Xero locationsNo
Expedition GPS activityNo
TidesNo

CYCLING FEATURES

Available cycling profilesBiking, indoor biking
Alerts (triggers alarm when you reach goals including time, distance, heart rate or calories)Yes
CoursesYes
MTB Grit & FlowNo
Cycle map (routable cycling-specific street map)No
Bike lap and lap maximum power (with power sensor)No
Race an activityYes
FTP (Functional Threshold Power)No
Compatible with Vector (Power Meter)No
Power Meter compatibleNo
Advanced cycling dynamics
Compatible with Varia Vision (head-mounted display)Yes
Compatible with Varia Radar (Rear-Facing Radar)Yes
Compatible with Varia LightsYes
Speed and cadence sensor support (with sensor)Yes (ANT+ and Bluetooth Smart sensors)

SWIMMING FEATURES

Available swim profilesPool swimming
Open-water swim metrics (distance, pace, stroke count/rate, stroke distance, swim efficiency (SWOLF), calories)No
Pool swim metrics (lengths, distance, pace, stroke count, swim efficiency (SWOLF), calories)Yes
Stroke type detection (freestyle, backstroke, breaststroke, butterfly) (pool swim only)Yes
Drill logging (pool swim only)Yes
Basic rest timer (up from 0) (pool swim only)Yes
"Repeat on" rest timer (pool swim only) (New)
Auto rest (pool swim only) (New)
Time and distance alertsNo
Pacing alerts (pool swim only) (New)
Countdown start (pool swim only)Yes
Pool swim workoutsYes
Critical swim speed (New)
Underwater wrist-based heart rateNo
Heart rate from external HRM (real-time during rests, interval and session stats during rests, and automatic heart rate download post-swim)No
ABOUT DEVICE

ABOUT DEVICE

Device name

Garmin Forerunner 645

Device type

Fitness/Sport smartwatch

Gender

Unisex

Predecessor

Successor

Models

Garmin Forerunner 645, Garmin Forerunner 645 Music

Date released

November, 2017

DISPLAY

DISPLAY

Display size

1.2 inches

Display type

LCD, Memory-in-pixel (MIP), transflective

Resolution

240 x 240 px

Pixel density

Customizable watchface

Yes

Input type

(not touchscreen), 5 Physical buttons

Always-On

Yes

BODY

BODY

Shape

Circular

Case material

Fiber-reinforced polymer

Strap material

Silicone

Bezel material

Stainless steel

Strap size

20 mm

Color

Black, Rose-gold, Sandstone

Screen protection

Dimension

42.5 x 42.5 x 13.5 mm

Weight

41.8 grams

Waterproof rating

Yes, 5ATM

Swim-proof

Yes, recommended

Durability test

CONNECTIVITY

CONNECTIVITY

Bluetooth calling

No

Bluetooth

ANT+, Bluetooth

Wi-Fi

Yes, Wi-Fi 802.11 b/g/n

NFC

Yes

MEMORY

MEMORY

RAM

ROM

Memory card slot

No

CELLULAR CONNECTIVITY

CELLULAR CONNECTIVITY

Network technology

None

SIM type

None

NOTIFICATIONS

NOTIFICATIONS

SMS alert

Yes

Calls alert

Yes

Email alert

Yes

Event reminder

Yes

MEDIA

MEDIA

Audio

No

Microphone

No

Loudspeaker

No

Bluetooth music

No

Camera

No

SENSORS

SENSORS

GPS

Galileo, GLONASS, GPS

Accelerometer

Yes

HRM

Yes

Gyroscope

Yes

Pulse Ox.

No

Altimeter

Yes

Barometer

Yes

Compass

Yes

ECG

No

Thermometer

Yes

Ambient light

Yes

HEALTH & FITNESS TRACKING

HEALTH & FITNESS TRACKING

Steps

Yes

Calories

Yes

Distance

Yes

Heart rate monitoring

Yes

Sleep tracking

Yes

Floors climbed

Yes

Blood oxygen

No

Blood Pressure

No

Stress

Yes

ECG tracking

No

Fall detection

No

Menstrual cycle

VO2 Max

Yes

Onscreen workout

No

Preloaded sport modes

Yes

BATTERY

BATTERY

Battery type

non-removable Lithium-polymer

Battery capacity

Battery life

GPS mode: 14hrs, Smartwatch mode: 7 days

Charging type

Charging dock

Charging duration

1-2 hours

Solar power

No

PLATFORM

PLATFORM

Operating system

Proprietary OS

Chipset

CPU

GPU

MISCELLANEOUS

MISCELLANEOUS

Companion app

Garmin Connect

Compatibility

Android, iOS

Payment system

Garmin Pay

Customizable strap

20mm, Yes

Voice Assistant

No

Find my phone

Yes

Box content

Charger, Garmin Forerunner 645, Manual, Straps

Reviews

There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.