25 Minute Timer
HIIT & Circuit Training

Interval Timer

Automated work/rest intervals for HIIT, Tabata, and circuit training. Maximize your workout efficiency with precise timing.

Try Interval Timer

Why Use an Interval Timer?

Interval training is more effective than steady-state cardio. Our timer ensures you never miss a work period or rest too long.

HIIT Workouts

High-Intensity Interval Training requires precise work/rest timing. 30 seconds work, 30 seconds rest - repeated. Our timer keeps you honest.

Circuit Training

Move through exercises with automatic timing. No need to check your watch - focus on form and intensity. The timer signals when to switch.

Tabata Protocol

20 seconds maximum effort, 10 seconds rest. 8 rounds. The science-backed fat-burning workout that improves both aerobic and anaerobic capacity.

Custom Intervals

Set your own work and rest periods. Adapt to any workout style or fitness level. From boxing rounds to EMOM, AMRAP to CrossFit WODs.

Group Classes

Perfect for fitness instructors. Everyone moves together with clear audio and visual cues. No confusion, just synchronized training.

Progressive Overload

Track your intervals over time. Decrease rest, increase work, or add rounds. Watch your fitness improve with measurable data.

Popular Interval Formats

Choose a proven protocol or create your own. These formats are used by athletes and fitness enthusiasts worldwide.

Tabata

Work: 20s
Rest: 10s
Rounds: 8
Total: 4 min

Original Tabata protocol - 4 minutes of maximum effort exercise. Proven to boost both aerobic and anaerobic fitness.

HIIT

Work: 30s
Rest: 30s
Rounds: 10
Total: 10 min

Balanced HIIT - equal work and recovery periods. Great for beginners building interval conditioning.

Circuit

Work: 45s
Rest: 15s
Rounds: 8
Total: 8 min

Strength circuits - longer work periods for resistance training with short recovery between stations.

Sprint

Work: 60s
Rest: 30s
Rounds: 6
Total: 9 min

Running intervals - build speed and endurance with longer work periods. Ideal for track workouts.

EMOM

Work: 60s
Rest: 0s
Rounds: 10
Total: 10 min

Every Minute on the Minute - complete reps within 60 seconds, rest the remainder. Great for skill work.

Boxing

Work: 180s
Rest: 60s
Rounds: 6
Total: 24 min

Traditional boxing rounds - 3 minutes of work, 1 minute of active recovery. Authentic fight training timing.

Complete Interval Training Guide

What is Interval Training?

Interval training alternates between high-intensity exercise and low-intensity recovery periods. Unlike steady-state cardio where you maintain a consistent pace, intervals push your body harder in short bursts followed by brief recovery.

This approach triggers excess post-exercise oxygen consumption (EPOC), often called the "afterburn effect." Your body continues burning calories at an elevated rate for hours after your workout. Studies show HIIT can burn 25-30% more calories than other types of exercise in the same time.

Benefits of Interval Training

  • ✓ Burn more calories in less time
  • ✓ Improve both aerobic and anaerobic fitness
  • ✓ Boost metabolism for hours after exercise
  • ✓ Build muscle endurance and power
  • ✓ No equipment required - bodyweight exercises work perfectly
  • ✓ Never boring - workouts fly by
  • ✓ Suitable for all fitness levels with proper modifications

How to Use This Interval Timer

  1. 1Choose your workout or set custom work and rest periods. Start with 30s work / 30s rest if you're new to intervals.
  2. 2Set the number of rounds. Beginners should aim for 6-8 rounds, advanced athletes can do 10-12.
  3. 3Prepare your exercises. Choose movements that work multiple muscle groups for maximum efficiency.
  4. 4Start the timer and give maximum effort during work periods. Use rest periods for active recovery, not complete rest.
  5. 5Cool down and stretch. Interval training is intense - proper recovery is essential.

Pro Tips for Effective Interval Training

  • • Quality over quantity - each work interval should be at true maximum effort
  • • Choose exercises you can perform safely at high speed (burpees, jump squats, mountain climbers)
  • • Use active recovery during rest periods (walking, slow jogging, dynamic stretching)
  • • Allow 48 hours between HIIT sessions for optimal recovery
  • • Progress gradually - decrease rest time or increase work time, not both at once

Why Interval Training Works

Time Efficient

Get maximum results in minimum time. A 20-minute HIIT workout burns more calories than an hour of steady-state cardio.

Afterburn Effect

EPOC keeps your metabolism elevated for 24-48 hours after exercise. Burn calories while you rest.

Heart Health

Improve cardiovascular fitness, VO2 max, and insulin sensitivity in just a few sessions per week.

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About Us

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Frequently Asked Questions

What is an interval timer used for?▼
An interval timer is used for workouts that alternate between periods of high-intensity exercise and rest. Common uses include HIIT (High-Intensity Interval Training), Tabata protocol, circuit training, sprint intervals, boxing rounds, CrossFit WODs, and any workout requiring precise work/rest timing. It automates the timing so you can focus on form and intensity.
What is the Tabata protocol?▼
Tabata is a specific HIIT protocol developed by Dr. Izumi Tabata. It consists of 8 rounds of 20 seconds maximum-intensity exercise followed by 10 seconds of rest, totaling 4 minutes. This specific ratio (2:1 work to rest) is scientifically proven to improve both aerobic and anaerobic capacity. Our interval timer can be set to exactly 20 seconds work and 10 seconds rest with 8 rounds.
What is the best interval timing for HIIT?▼
The best HIIT interval timing depends on your fitness level and goals. Beginners often start with 30 seconds work and 30 seconds rest (1:1 ratio) to build conditioning. Intermediate athletes might use 40 seconds work and 20 seconds rest (2:1 ratio). Advanced protocols like Tabata use 20 seconds work and 10 seconds rest (2:1). The key is maintaining high intensity during work periods.
How many intervals should I do for HIIT?▼
Most HIIT workouts consist of 8-12 intervals, totaling 15-25 minutes. Tabata uses exactly 8 intervals (4 minutes total). Beginners should start with 6-8 intervals, while advanced athletes may do 10-12. Quality matters more than quantity—each work interval should be at maximum effort. Our timer allows you to customize the number of rounds to match your fitness level.
Can I use this interval timer for circuit training?▼
Absolutely! Circuit training is one of the best uses for an interval timer. Set work periods (typically 45-60 seconds) for each exercise station and rest periods (15-30 seconds) for transitioning between stations. The timer keeps everyone moving together in group classes or helps you maintain pace during solo workouts. No need to look at your watch—focus on proper form.
Is this interval timer free?▼
Yes, our interval timer is completely free forever with no sign-up required. All features including custom work/rest intervals, unlimited rounds, visual and audio alerts, and mobile responsiveness are available at no cost. We believe fitness tools should be accessible to everyone.
What's the difference between HIIT and Tabata?▼
HIIT (High-Intensity Interval Training) is a general term for any workout alternating high and low intensity. Tabata is a specific HIIT protocol with fixed timing: 20 seconds maximum effort, 10 seconds rest, repeated for 8 rounds (4 minutes total). While all Tabata is HIIT, not all HIIT is Tabata. HIIT can use various work/rest ratios, but Tabata always uses the specific 2:1 ratio proven in research studies.
How often should I do interval training?▼
For most people, 2-3 HIIT sessions per week is optimal. Interval training is intense and requires adequate recovery time. Beginners should start with 1-2 sessions per week and gradually increase. Always allow at least 48 hours between HIIT workouts for the same muscle groups. Listen to your body—overtraining can lead to injury and decreased performance.

Train Smarter with Intervals

Interval training burns more calories in less time. Start using interval timers for more effective workouts.

Start Interval Training

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HTML Embed Code
<iframe
  src="https://25mintimer.com/embed/timer/25/"
  width="100%"
  height="600"
  frameborder="0"
  title="Interval Timer"
  style="border-radius: 12px; box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);">
</iframe>
Features
  • ✓ Fully functional timer
  • ✓ Sound notifications included
  • ✓ Responsive design (mobile-friendly)
  • ✓ No attribution required (but appreciated!)
  • ✓ Updates automatically
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