HIIT & Interval Workout Timer Guide (Free Online)

Why Use an Interval Timer for Workouts

Interval training demands precise timing. A HIIT timer or Tabata timer keeps honest seconds between work and rest, and the difference between 20 seconds and 25 seconds matters when you’re mid-burpee. Push yourself with a timer instead of guessing.

CleanStopwatch works as a free interval timer. No app download. No signup. Open it on any device — phone, tablet, laptop — and customize the timing for any workout format.

Common Interval Workout Formats

Format	Work	Rest	Rounds	Total Time
Tabata	20s	10s	8	4 min
HIIT (standard)	45s	15s	8-12	8-12 min
HIIT (long)	60s	30s	6-10	9-15 min
Circuit training	40s	20s	3-5 per circuit	Variable
EMOM	60s	Varies	10-20	10-20 min
Rowing/sprint intervals	30s	90s	6-10	12-20 min

How to Set Up Workout Intervals

For Tabata (20s work / 10s rest)

Open the timer and set it to 4 minutes countdown. Start the timer and switch between 20s of max effort and 10s of rest on your own. For an automated approach, use the Pomodoro mode with custom intervals — set work to 20s and break to 10s, then run 8 cycles.

For HIIT (45s work / 15s rest)

Set a countdown for your total workout duration (e.g., 12 minutes for 12 rounds). Use the stopwatch mode in laps to mark each round. Or set Pomodoro mode with 45s work / 15s break and let it cycle automatically.

For Custom Circuits

The Configurator lets you save preset timers for each workout type. Create a “Tabata” preset, a “HIIT 45/15” preset, and a “Circuit” preset. Each one remembers your settings so you can start workouts instantly without reconfiguring.

Display Options for Gym Use

Setup	How	Best For
Phone in pocket	Set audio alert volume high	Running, rowing
Tablet on floor	Full screen, font large enough to read from standing position	Floor exercises, yoga
Gym TV / monitor	Large display across the room	Group classes, home gym
Smartwatch via browser	Open in watch browser (if available)	Quick glance intervals

Open the Configurator to maximize font size and enable fullscreen (press F to hide browser controls). For floor workouts, place your device at eye level — you don’t want to stop mid-squat to check the time.

Timer Tips for Different Workouts

Bodyweight circuits. Use a 40s work / 20s rest ratio. Three rounds through 5 exercises takes exactly 15 minutes. Keep the timer in fullscreen mode so you can see it from any position.

Treadmill / cardio intervals. Use 60s work / 60s rest for five rounds — that’s a 10-minute cardio block. Rest intervals let your heart rate come down before the next push.

Strength training rest periods. Set a 90s countdown between sets. Start it when you finish a set. When it rings, start your next set. Consistent rest periods lead to better training volume tracking.

Yoga or stretching flows. Use countdown mode for pose holds. Set 30-60 seconds per pose and work through a sequence without watching the clock. Focus on the pose, let the timer handle the duration.

EMOM (Every Minute on the Minute). Set a stopwatch counting up. Start each exercise at the top of the minute. The timer tracks elapsed time so you know exactly where you are in the workout. Press L to mark each completed round.

Sound Settings for Workouts

In the Configurator, you can choose from starter sounds (Default Chime and Classic Beep) or the full sound library with a Pro subscription. For gym use:

• Loud environment (group class) — choose a sound that cuts through noise. Classic Beep is sharp and audible even with music playing.
• Quiet environment (home workout) — any sound works. Keep the volume moderate.
• No audio (library/etc.) — rely on the visual countdown. The large digits are readable from across the room.

Pro tip: enable desktop notifications in the Configurator so you get a visual alert even if the sound is off.

Quick Start

1. Open Configurator — set countdown to your workout duration
2. Adjust font size and enable fullscreen
3. Pick your alert sound
4. Save the preset and use it for every workout

Start your interval session: cleanstopwatch.com/configurator

Related Guides

• The Complete Guide to Pomodoro Technique — Adapt interval timing for study and focus sessions.
• How to Use the Stopwatch with Lap Tracking — Track lap splits for run and row intervals.