ROUNDS
10
00:40
REST
00:20
A free, fully customisable online interval timer for HIIT, Tabata, circuit training and any workout that alternates work and rest. Set your work time, rest time and number of rounds, or choose one of the built-in presets to get started in seconds. A sound cue fires at every transition so you never need to glance at the screen during a set.
Choose from Tabata (20s/10s ×8), HIIT (40s/20s ×10), 30/30, 45/15 or 60/30 presets — or dial in any combination you like using the + and − controls. The timer tracks your current round, shows work vs rest phases in different colours, and plays a warning beep 5 seconds before each work interval ends.
| Protocol | Work | Rest | Rounds | Total time |
|---|---|---|---|---|
| Tabata | 20 sec | 10 sec | 8 | 4 min |
| HIIT | 40 sec | 20 sec | 10 | 10 min |
| 30/30 | 30 sec | 30 sec | 10 | 10 min |
| 45/15 | 45 sec | 15 sec | 8 | 8 min |
| 60/30 | 60 sec | 30 sec | 6 | 9 min |
| Sprint interval | 30 sec | 90 sec | 6 | 12 min |
| Pyramid | 60 sec | 60 sec | 5 | 10 min |
Tabata is a specific high-intensity protocol developed by Japanese exercise scientist Dr Izumi Tabata and colleagues at the National Institute of Fitness and Sports in Tokyo. The landmark 1996 study used 20 seconds of maximum-effort cycling followed by 10 seconds of rest, repeated 8 times for a total of 4 minutes. The study found this short protocol improved both aerobic capacity (VO2max) and anaerobic capacity more effectively than 60 minutes of moderate steady-state exercise.
The key word is maximum effort. A light jog performed in a 20/10 pattern is not Tabata — it is merely a short interval workout. True Tabata requires working at or above 170% of VO2max during each work interval, which means choosing exercises intense enough that the final two rounds feel nearly impossible to complete.
Effective Tabata exercises include sprint cycling, burpees, kettlebell swings, box jumps, squat jumps and rowing. Exercises with a slow eccentric phase — like standard push-ups — are harder to perform at the required intensity within 20 seconds.
High-Intensity Interval Training (HIIT) is a broader category of workout where short bursts of intense effort alternate with recovery periods. Unlike Tabata's strict 20/10 protocol, HIIT intervals are flexible — work-to-rest ratios range from 1:1 to 1:3 depending on fitness level and goals.
The physiological benefits of HIIT are well documented. Research published in the Journal of Sport and Health Science has shown that HIIT produces comparable cardiovascular improvements to much longer moderate exercise sessions in a fraction of the time. HIIT also triggers a pronounced EPOC effect (excess post-exercise oxygen consumption) — elevated calorie burn that continues for hours after the workout ends, sometimes referred to as the "afterburn effect."
Longer rest periods (1:2 or 1:3 ratio) are suitable for beginners or heavy compound movements like deadlifts and cleans where proper form under fatigue is a priority. Shorter rests (1:1) push cardiovascular adaptation further and suit intermediate to advanced practitioners.
1:3 ratio (e.g. 20s work / 60s rest): Best for beginners, heavy barbell work, plyometrics, or sprint-based workouts where maximum effort is the goal and full recovery between sets is needed to maintain quality.
1:2 ratio (e.g. 30s work / 60s rest): Good general-purpose HIIT. Allows high effort with partial recovery. Suitable for most body-weight and moderate-load exercises.
1:1 ratio (e.g. 40s work / 40s rest): Harder cardiovascular challenge. Work quality will decline in later rounds — choose exercises you can perform safely at reduced intensity, such as mountain climbers, jumping jacks or rowing.
2:1 ratio (e.g. 40s work / 20s rest): Very demanding. Reserve for experienced athletes or low-impact exercises like cycling or rowing where form breakdown is less of a safety concern.
A balanced interval session typically consists of a 3–5 minute warm-up at moderate intensity, 4–8 working rounds with your chosen work/rest ratio, and a 3–5 minute cool-down. For beginners, 4 rounds of the 40/20 preset is a manageable starting point; intermediate practitioners often work up to 8–10 rounds of 40/20 or the full 8-round Tabata protocol.
Pair exercises that use different muscle groups to allow partial recovery — for example, alternating upper-body and lower-body movements, or pairing a push exercise (push-ups) with a pull exercise (rows). This lets you maintain higher intensity for more rounds than repeating the same movement.
For fat loss, 3–4 HIIT sessions per week with at least one rest day between sessions is a widely recommended guideline. More frequent sessions increase the risk of overtraining and injury without proportional additional benefit.
The original Tabata protocol is exactly 8 rounds — 4 minutes total. This is one complete set. Many people perform multiple Tabata sets with a 1–2 minute rest between sets, or combine several different exercises each performed for one 8-round set. Starting with one set per exercise is enough for most beginners.
They serve different purposes. HIIT is highly time-efficient and produces strong cardiovascular and metabolic adaptations. Steady-state cardio (jogging, cycling at moderate pace) is easier to recover from, better for active recovery days, and is associated with different physiological benefits including improved fat oxidation at rest. Most fitness programmes benefit from including both.
Due to its high intensity, a full HIIT session is typically 20–30 minutes including warm-up and cool-down. The actual high-intensity work portion is usually 10–20 minutes. Sessions longer than 30 minutes of intense intervals are difficult to sustain at the required effort level and increase injury risk without proportional benefit.
2–3 sessions per week with at least one full rest day between sessions is the widely recommended guideline for most people. The recovery demand of genuine high-intensity training is significant, and training daily without rest is counterproductive.
Yes. Set the work time to match your set duration (e.g. 45 seconds) and the rest time to your desired recovery period (e.g. 60–90 seconds). The timer will keep your rest periods consistent, which is important for managing training volume and progressive overload.
For boxing and martial arts-specific round timing, try the fight timer. For productivity intervals at work, try the Pomodoro timer. Back to the homepage for all our free online timers.