4 x 4 Exercise Timer

Perfect for interval training and workout routines

Rest Time (Optional)

Leave both at 0 for continuous intervals without rest periods.

WORK TIME
04:00
Interval 1 of 4
Total Time: 32:00

🔊 Enable sound for audio alerts on mobile devices

How to Use Exercise Timer

Set Work Duration: Choose your exercise duration between 10 seconds and 30 minutes using the work time inputs.

Set Rest Duration (Optional): Add rest time between intervals for HIIT workouts. Leave at 0 for continuous intervals.

Set Repetitions: Choose how many intervals you want to complete (1-30 repetitions).

Start Timer: Click the Start button to begin. The timer will alternate between work (green) and rest (blue) phases.

Sound Alerts: A 1-second alarm will sound at the end of each work and rest phase. Click "Enable Sound" for mobile audio, which includes vibration fallback. Use the sound button to mute/unmute.

Controls: Pause to take a break, or reset to start over. Your settings are automatically saved.

Sleep Mode Fix: Timer now continues accurately even when your phone goes to sleep! The âš¡ button keeps your screen awake (shows ON/OFF and turns green when active).

Mobile Features: Includes vibration alerts when sound fails, Web Audio API for better mobile compatibility, and Service Worker for background timer continuation.

Perfect Exercise Examples

Endurance Intervals

Long-form aerobic and anaerobic training

  • • 4 minutes intense work, 4 minutes active recovery
  • • 4 rounds (32 minutes total)

HIIT Workouts

High-Intensity Interval Training with work/rest cycles

  • • 45 seconds work, 15 seconds rest
  • • 8-12 repetitions per workout

Tabata Training

Classic 4-minute high-intensity protocol

  • • 20 seconds intense exercise, 10 seconds rest
  • • 8 rounds (4 minutes total)

Circuit Training

Move between different exercise stations

  • • 60 seconds per station
  • • 6-10 different exercises

Boxing Rounds

Traditional boxing training intervals

  • • 3 minutes work rounds
  • • 3-12 rounds per session

Yoga & Stretching

Hold poses for specific durations

  • • 30-60 seconds per pose
  • • 5-15 different poses

Strength Supersets

Back-to-back exercises without rest

  • • 45-60 seconds per exercise
  • • 4-8 supersets

Cardio Intervals

Alternate between high and low intensity

  • • 2-4 minutes high intensity
  • • 5-10 intervals

Calisthenics

Bodyweight exercises with timed sets

  • • 30-90 seconds per exercise
  • • 6-12 exercises per routine

CrossFit WODs

Workout of the Day interval timing

  • • EMOM (Every Minute on the Minute)
  • • 10-20 minute workouts