Free Online Interval Timer

An interval timer cycles between work and rest periods for a set number of rounds. Configure the duration of each phase, press Start, and focus entirely on your activity — the timer handles transitions automatically with audio cues and color-coded phases.

Configuration: Set work (5–3,600s), rest (0–3,600s), and rounds (1–100). Use the presets for common setups or dial in your own values. Set rest to 0 for consecutive work intervals with no break.

Warm-up & cool-down: Both are optional (0–300s). Warm-up runs once before the first work interval, after a 3-second "Get Ready" countdown. Cool-down runs once after the final round. These phases appear with distinct colors so you always know where you are.

During your session: Phase labels are color-coded — red for Work, green for Rest, amber for Warm Up and Get Ready, blue for Cool Down. The progress ring shows time remaining within each phase. The round badge tracks your progress through all rounds. No rest plays after the final work interval.

Controls: Space to start or pause, R to reset, Escape to stop. All settings save automatically and persist across sessions.

An interval timer is a training tool that alternates between periods of activity (work) and recovery (rest) for a specified number of cycles. Unlike a simple countdown timer that runs once, an interval timer repeats the work-rest pattern automatically, handling all transitions and providing audio cues at each phase change.

Interval training is used across fitness, sports, rehabilitation, and even productivity. The core principle is simple: structured alternation between effort and recovery. The timer removes the mental overhead of tracking phases and lets you focus on the activity itself.

This timer goes beyond basic work/rest by supporting optional warm-up and cool-down phases. A warm-up prepares your body before the first high-intensity work interval. A cool-down provides a gradual transition after the final round. Both run once per session and are fully optional.

Tabata is a specific interval protocol: 20 seconds work, 10 seconds rest, 8 rounds. It was developed for maximum effort in minimal time and follows a fixed 2:1 work-to-rest ratio.

This interval timer is fully customizable. Work can range from 5 seconds to 60 minutes. Rest can be set to zero for consecutive work blocks or extended for recovery-focused sessions. You can run up to 100 rounds and add warm-up and cool-down phases that Tabata doesn't include.

Use the Tabata timer when you want the classic 20/10 protocol or minor variations of it. Use the interval timer when you need full control over every parameter — longer work periods, zero-rest drills, warm-up phases, or sessions with many rounds. For HIIT-specific presets matched to experience level, try the HIIT timer. For structured focus sessions outside of exercise, try the Pomodoro timer.

HIIT Workouts

High-intensity interval training pairs short bursts of all-out effort with recovery periods. Common formats include 30/30 (equal work and rest), 40/20 (work-heavy), and 60/30 (endurance-focused). Set the ratio that matches your fitness level and goals.

Circuit Training

Use the work phase for each exercise station and the rest phase as transition time between stations. A typical circuit might use 45 seconds of work with 15 seconds of rest across 8–12 stations.

Running and Cycling

Alternate between hard effort and easy recovery. A common running interval is 60 seconds fast with 60–90 seconds jogging, repeated for 6–10 rounds. Add a warm-up jog and cool-down walk using the built-in phases.

Stretching and Mobility

Hold each stretch for a set duration (work phase) with a brief transition period (rest phase) between positions. Set rest to 5–10 seconds for quick transitions or 0 for continuous stretching with audio cues marking each hold.

Match intervals to your goal. Short work with equal or longer rest (20/20, 15/30) builds power and speed. Longer work with shorter rest (60/15, 45/15) builds endurance. Choose work-to-rest ratios that align with what you're training.

Use warm-up and cool-down. Even 60 seconds of light movement before your first work interval reduces injury risk and improves performance. A cool-down helps your heart rate return to normal gradually.

Start with fewer rounds. If you're new to interval training, begin with 4–6 rounds and build up over weeks. Quality of effort matters more than volume — 6 rounds at full intensity beats 12 rounds at half effort.

Set rest to zero for timed drills. When you want consecutive work periods with only an audio cue between them (no recovery), set rest to 0. The timer plays a transition sound at each round boundary so you know when to switch exercises. Use a countdown timer for standalone timed activities.