TL;DR: Every interval workout comes down to two numbers: how long you push and how long you rest. Pick a format (Tabata is 20 seconds on, 10 off), set a short repeating timer, and let the beeps run the workout so you can focus on moving. A loop timer plus a plain second counter is all the gear you need.
The two numbers that run every workout
Interval training sounds fancy, but it's really just work and rest, traded back and forth. The "work" number is how long you go hard. The "rest" number is how long you recover before the next round. Change those two numbers and you change the whole workout.
- Longer work, shorter rest = harder on your heart and lungs, more conditioning.
- Shorter work, longer rest = more power and speed, less gassed.
- Equal work and rest (like 30/30) = a balanced middle ground that's great for beginners.
The trick is that you can't watch a clock and give full effort at the same time. That's why a hands-free timer matters. You set the numbers once, then react to sound instead of staring at a screen. When the beep says go, you go. When it says stop, you rest. Your brain gets to check out and your body gets to work.
Common interval formats, side by side
Here are the formats you'll actually use, with realistic round counts and total times. Beginners should start on the shorter, easier end and add rounds over weeks, not days.
| Format | Work | Rest | Rounds | Total time |
|---|---|---|---|---|
| Tabata | 20 sec | 10 sec | 8 | 4 min |
| 30/30 (classic HIIT) | 30 sec | 30 sec | 8–10 | 8–10 min |
| 30/15 | 30 sec | 15 sec | 8–12 | 6–9 min |
| 40/20 | 40 sec | 20 sec | 8–10 | 8–10 min |
| EMOM | ~40 sec | rest of the minute | 10–20 | 10–20 min |
| Sprint intervals | 30 sec | 2–4 min | 4–6 | 10–20 min |
Tabata (20/10)
Tabata is the most famous short format for a reason: it's brutal and it's quick. You do 20 seconds all-out, rest 10 seconds, and repeat that eight times. That's four minutes total. The dedicated Tabata timer advances through all eight work and rest rounds automatically; use a quick 20-second timer when you only need one round. Pick one hard move (air squats, burpees, mountain climbers) and don't pace yourself, that misses the point.
EMOM (every minute on the minute)
EMOM means you start a new set at the top of every minute. Say your target is 10 push-ups. You do them, then rest for whatever's left of that minute before the next one starts. Do more reps and you earn less rest, which keeps you honest. The EMOM timer counts the rounds and marks every new minute; a repeating one-minute timer also works when the minute mark is your only cue. Run it for 10 to 20 minutes depending on how fresh you feel.
Circuits and rounds
A circuit strings several moves together with short breaks. A simple one: 40 seconds of work, 20 seconds of rest, five different exercises, repeated for three rounds. That's 15 minutes of moving. A HIIT timer handles that work/recovery pattern hands-free. Circuits are forgiving because you're switching muscles, so you can keep going longer than an all-out Tabata.
Timing rest between strength sets
Interval timing isn't just for cardio. If you lift weights, resting the right amount between sets is what makes the next set count. Too little rest and you can't lift heavy. Too much and your session drags on forever. Here's a sane starting guide:
- Heavy strength (low reps, big lifts): 2 to 5 minutes. Full recovery so you can move real load.
- Muscle building (moderate reps): 60 to 90 seconds. Enough to recover, short enough to keep tension high.
- Endurance or "pump" work: 30 to 45 seconds. Keep the burn going.
The honest truth is that most people guess at rest and end up scrolling their phone for four minutes. A simple 30-second rest timer fixes that overnight. Start it the second you rack the weight, and when it beeps, you're up. You'll get more done in less time, and your workouts get shorter without getting easier.
Setting it up on timer.now
You don't need an app or a fancy watch. Two features cover almost everything.
Short second timers. Most interval work lives in the 10-to-60-second range, so being able to set a timer in seconds quickly is the whole game. Type the number, hit start, and you get a big clear countdown with a sound at zero. Bookmark the exact lengths you use most so they're one tap away.
Build the phases. The custom interval timer alternates work and recovery and counts the rounds for you. For combat training, the boxing timer uses named rounds, rests and familiar bell cues. Choose the specialist page when its defaults fit, or build a neutral work/rest routine for everything else.
A clean way to handle work-and-rest is to run two short timers back to back: one for the push, one for the recovery. When the work timer beeps, glance up, start the rest timer, and breathe. It sounds low-tech because it is, and that's exactly why it never crashes or nags you mid-burpee.
A sample 20-minute session
Here's how the pieces fit into a real workout you could do today:
- Warm up: 3 minutes easy, loose and unhurried.
- Block one, Tabata: 20 on / 10 off, 8 rounds of squats (4 min).
- Rest: 1 minute, walk it off.
- Block two, 40/20 circuit: push-ups, lunges, mountain climbers, 3 rounds (9 min).
- Cool down: 3 minutes of slow breathing and stretching.
Add it up and you're right around a tidy 45-minute session once you include changing shoes and refilling your water. If you're short on time, drop block two and you've still done something real in under 10 minutes. For more workout and focus timing ideas, the timer.now blog has plenty.
The bottom line
Interval training is just work and rest on repeat, so pick two numbers and let a timer enforce them. Start with a friendly format like 30/30 or a 4-minute Tabata, use a short repeating second timer, and add rounds as you get fitter. The less you think about the clock, the harder you can actually train.
Frequently asked questions
What's a good work-to-rest ratio for HIIT?
What does EMOM mean?
How do I time intervals?
Sources
Keep reading: Triathlon Timing: Splits, Transitions and Training, How to Use an Online Stopwatch: Laps, Splits and Tips, and How Long Is a Tabata Workout? (And Why 4 Minutes Works).