Free Interval Timer Online
The all-in-one interval timer for HIIT, Tabata, EMOM, boxing, and custom WOD workouts. Set your work and rest intervals, press start, and train with sound alerts and fullscreen mode.
Quick Presets
How to Use This Interval Timer
1. Choose Your Mode
Select from HIIT, Tabata, EMOM, AMRAP, Boxing, or Custom mode. Each mode loads optimized defaults for that training style.
2. Set Your Intervals
Adjust work time, rest time, number of rounds, and prepare countdown using the +/- buttons. The total workout time updates instantly.
3. Press Start
A prepare countdown gives you time to get ready. The timer then alternates between work and rest with clear sound alerts at each transition.
4. Share Your Timer
Click Share to copy a link with your exact timer settings. Send it to training partners, students, or save it for later use.
The Ultimate Guide to Interval Training and WOD Clocks
Interval training is one of the most effective fitness strategies for building cardiovascular endurance, burning fat, and improving athletic performance. Unlike steady-state exercise, where you maintain a constant pace, interval training alternates between periods of high-intensity effort and active recovery. To execute these workouts properly, athletes rely on a professional interval timer or WOD clock to manage their pacing.
What is HIIT (High Intensity Interval Training)?
High-Intensity Interval Training, commonly known as HIIT, involves short bursts of intense exercise followed by brief rest intervals. When you perform HIIT, you push your heart rate to 80 percent or more of its maximum capacity during work phases. Using an online workout timer allows you to stay focused on execution rather than looking at a clock, optimizing the metabolic benefits of your session.
The History and Development of WOD Clocks in Functional Fitness
In functional fitness and CrossFit, workouts are often structured as a WOD (Workout of the Day). Traditional gyms used manual stopwatches, but the rise of functional training demanded advanced tracking. Modern digital WOD clocks automate various workout styles including AMRAP, EMOM, and Tabata. Our online gym timer acts as a digital WOD clock, giving you the same precision as hardware gym wall clocks without the premium price tag.
Comparing Popular Workout Timer Presets
Depending on your specific goals, different interval training structures are appropriate. The table below outlines the default configurations of the most popular timer presets:
| Protocol Name | Default Work / Rest | Default Rounds | Target Fitness System | Primary Benefit |
|---|---|---|---|---|
| HIIT | 30s work / 15s rest | 10 rounds | Aerobic and Anaerobic | Calorie burn and metabolic conditioning |
| Tabata | 20s work / 10s rest | 8 rounds | Anaerobic Capacity | Maximum oxygen uptake and speed |
| EMOM | 40s work / 20s rest | 10 rounds | Pacing and Strength | Volume management and work capacity |
| AMRAP | Time Cap (no rest) | 1 round | Muscular Endurance | Mental toughness and round tracking |
| Boxing | 3:00 work / 1:00 rest | 12 rounds | Cardio and Technique | Fighter conditioning and sparring pace |
Advanced Tips for Custom Workouts
If you are designing a custom circuit training routine, keep these principles in mind:
- Work-to-Rest Ratio: Beginners should start with a 1:2 ratio (e.g., 20 seconds work, 40 seconds rest). As conditioning improves, progress to 1:1 (e.g., 30s/30s) or 2:1 (e.g., 40s/20s).
- Workout Duration: Keep high-intensity sessions under 30 minutes total. If you can train at high intensity longer than that, you are likely not pushing hard enough during the work phases.
- Preparation Time: Always set a prepare countdown of at least 5 to 10 seconds. This allows you to assume the correct exercise position before the first round begins.
How Web Audio Alerts and Screen Wake Lock Improve Your Training
Standard timers fail during home workouts because the screen goes to sleep or you cannot hear the start of the next phase. Our fitness timer uses the Screen Wake Lock API to prevent your mobile phone or computer from dimming or locking while the workout is active. Additionally, HTML5 Web Audio generates high-quality beep signals that cut through your workout music, keeping you in sync with every round transition.
Frequently Asked Questions
What is an interval timer?
An interval timer is a countdown timer that alternates between work and rest periods for a set number of rounds. It is the essential tool for HIIT, Tabata, CrossFit, boxing, and circuit training. This timer automates the timing so you can focus entirely on your workout.
What is the Tabata protocol?
The Tabata protocol was developed by Japanese researcher Dr. Izumi Tabata in 1996. It consists of 20 seconds of all-out intensity followed by 10 seconds of rest, repeated for 8 rounds (4 minutes total). Studies showed it improves both aerobic and anaerobic capacity simultaneously.
How does EMOM training work?
EMOM (Every Minute On the Minute) training starts a new round at the beginning of each minute. You perform your prescribed reps, then rest for the remainder of that minute. The faster you finish, the more rest you get. This creates a built-in incentive to maintain intensity.
What is a WOD clock?
A WOD (Workout of the Day) clock is a timer used in CrossFit and functional fitness programming. It tracks structured intervals for various workout formats including AMRAP, EMOM, For Time, and custom interval schemes. This timer serves as a full WOD clock.
Can I use this as a boxing round timer?
Yes. Select Boxing mode for standard 3-minute rounds with 1-minute rest periods. You can adjust round length for amateur boxing (2 minutes), professional boxing (3 minutes), or MMA (5 minutes). The number of rounds is fully customizable from 1 to 99.
Does the timer work on mobile?
Yes, fully. The timer is responsive and works on all modern mobile browsers including Safari on iPhone and Chrome on Android. Sound alerts play through your device speaker. For the best experience, keep your phone volume up and do not switch to another app.
Will the screen stay on during my workout?
Yes, if your browser supports the Screen Wake Lock API (Chrome, Edge, Opera, and Samsung Internet). The timer automatically requests a wake lock when you press Start, preventing your screen from dimming or locking during your workout.