Random Interval Timer
Keep your device volume on for the sound signal.
About this tool
A random interval timer beeps at unpredictable intervals between your chosen minimum and maximum time, repeating automatically until you stop it. Set the range, press Start and react to each signal — ideal for workout drills, reaction games and any activity where a steady, predictable beat would be too easy to anticipate. Choose your beep sound, show or hide the countdown to the next signal, and track your reps.
How to use it
- Set the interval range in seconds, or tap a preset.
- Choose your beep sound and options.
- Tap Start — it beeps at a fresh random interval each time.
- React to every beep; tap Stop when you're done.
What people use it for
- Workout & HIIT drills — unpredictable work/rest signals so you can't coast.
- Reaction training — sprints, direction changes or drills on a random cue.
- Musical Chairs & party games — a fresh random stop every round.
- Mindfulness bells — an occasional chime to pause and check in.
Random vs fixed interval timer
A fixed interval timer beeps on a steady beat, so your body soon anticipates the next signal. A random interval timer draws a new gap between your minimum and maximum each time, so every beep is a genuine surprise — which is exactly what makes reaction drills sharper and workouts harder to game. It runs entirely in your browser with nothing to install.
Picking an interval range
| Activity | Suggested range |
|---|---|
| Reaction drills & agility | 10–30 sec |
| HIIT / circuit work | 20–60 sec |
| Musical Chairs & party rounds | 15–45 sec |
| Mindfulness / posture reminders | 3–10 min |
Frequently asked questions
- How does the random interval timer work?
- Set an interval range and tap Start; it beeps at a fresh random interval each time and keeps going until you stop it, counting your reps as it goes.
- Does it repeat automatically?
- Yes — it re-rolls a new random interval after every beep and keeps signalling until you stop it, so you never settle into a rhythm.
- Can I run it with music?
- Yes — play your own music or a podcast in another app and the interval timer just adds the beeps on top, so it fits workouts and drills without needing its own soundtrack.
- Is it good for workouts?
- Very — unpredictable intervals stop you from pacing to the clock, which keeps HIIT drills, reaction training and agility work honest and engaging.
- Is it free and private?
- Completely free, no sign-up. Everything runs in your browser, so nothing you type is uploaded.