Free Online Interval Timer

Create custom work and rest intervals

An online interval timer alternates between timed phases instead of stopping after one countdown. Set how long each work period lasts, how much recovery or transition time follows it, and how many rounds should repeat. The full sequence is prepared before you press Start, so you can focus on the activity instead of resetting a separate timer after every phase.

Use the general setup for exercise circuits, study cycles, presentation practice, debate turns, station rotations or any routine that needs consistent phase timing. The online interval timer accepts 1–99 rounds and also supports an optional warm-up and cool-down around the repeating sequence.

• Set work and rest durations in seconds for precise short or long intervals.
• Choose 1–99 rounds and see the total session structure before starting.
• Add optional warm-up and cool-down phases without creating another timer.

Choose a 40/20 interval timer or another preset

Four presets cover common starting points while keeping every value editable. Work / rest starts at 60 seconds of activity and 30 seconds of rest for five rounds. The 40/20 interval timer preset uses 40 seconds of work and 20 seconds of rest for eight rounds. Classroom rotation uses 10-minute activity blocks with two-minute transitions for four rounds, while Circuit uses equal 30-second phases for ten rounds.

A preset is only a shortcut. After selecting one, open Settings to change the duration, round count, phase order or alert. The online interval timer keeps your latest configuration in this browser, making it easier to return to the same routine without creating an account.

• Work / rest: 60 seconds work, 30 seconds rest, 5 rounds.
• 40/20 Work–Rest: 40 seconds work, 20 seconds rest, 8 rounds.
• Classroom rotation: 10 minutes work, 2 minutes transition, 4 rounds.
• Circuit: 30 seconds work, 30 seconds rest, 10 rounds.

Alerts and full-screen progress

Sound cues let participants follow the routine without watching every second. Choose three beeps, a 10-second warning, a single short or long beep, an alternating beep, bell, chime or soft tone. The current phase name, round number, remaining time and session progress stay visible, so the timer remains usable when sound is muted or unavailable.

Full-screen mode removes the surrounding page and keeps the active phase, large countdown, timeline and essential controls on screen. The online interval timer is therefore easy to follow on projectors, shared displays and training-space screens from a distance.

• Preview alert sounds before starting the session.
• Follow visual phase and progress feedback when the device is muted.
• Use full screen for a distraction-free classroom or workout display.

How to use the online interval timer

Choose a preset or open Settings and enter your own work time, rest time and rounds. Click the large countdown or the Start button to begin. While the session is active, use Previous or Skip to move between phases, Pause when the group needs more time, and Reset to return to the beginning.

The online interval timer shows every active and recovery phase in order on the upcoming-interval timeline. Completed phases become visually muted, and any available phase can be selected to jump directly to it. Elapsed time, the current round and total remaining time provide a quick summary without opening the settings panel.

• Select a preset or customize the full routine before starting.
• Click the large time to start, pause or resume without finding a small control.
• Use the phase timeline to review or jump to another interval.

When to use a custom interval timer

Teachers can use repeated intervals for learning stations, partner exchanges, timed discussion turns and activity-to-cleanup transitions. Coaches and individuals can time circuits, mobility work or alternating effort and recovery. The same structure also works for focused work blocks, rehearsal drills and meeting activities where every participant needs a shared visual pace.

Use the built-in 40/20 interval timer preset when neutral Work and Rest labels fit the activity. For workout-specific High intensity and Recovery labels, use the HIIT timer. For the classic four-minute 20/10 protocol, use the Tabata timer. Keeping those modes separate lets this online interval timer remain focused on flexible, custom phase sequences.