What is the difference between HIIT and Tabata?

Tabata is a specific HIIT protocol: 20 seconds on, 10 seconds off, 8 rounds, four minutes total. HIIT is the broader category — any structured alternation of high-effort and rest intervals qualifies. All Tabata is HIIT, but not all HIIT is Tabata. HIIT intervals can range from 15 seconds to several minutes depending on the workout goal.

How many days a week should I do HIIT?

Most fitness guidelines recommend 2–3 HIIT sessions per week for non-athletes, with at least 48 hours of recovery between sessions. HIIT creates significant metabolic and neuromuscular fatigue, and insufficient recovery increases injury risk and leads to diminishing returns. Pair HIIT days with lower-intensity active recovery or strength training on alternate days.

Is HIIT better than steady-state cardio for fat loss?

Research shows HIIT produces comparable or superior fat loss in less time compared to moderate-intensity steady-state exercise. The key advantages are the EPOC afterburn effect and higher training density. However, steady-state cardio is lower in injury risk and easier to sustain long-term. An optimal program combines both modalities.

What heart rate zone should I target during HIIT work intervals?

During HIIT work intervals, aim for 80–95% of your maximum heart rate (estimated as 220 minus your age). If you cannot hold a conversation during the work phase, you are in the right zone. During rest intervals, allow your heart rate to recover to 60–70% of max before the next work period begins.

HIIT Timer

Free HIIT timer with customizable work and rest intervals. Perfect for high-intensity interval training at home or the gym. Set rounds, work duration, and rest periods instantly.

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Rest

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High-Intensity Interval Training (HIIT) is a broad training methodology defined by alternating bouts of intense effort — typically 80–95% of maximum heart rate — with structured recovery periods. Unlike the fixed 20/10 protocol of Tabata, HIIT intervals are highly adaptable: work periods commonly range from 20 seconds to 4 minutes, and rest ratios vary from 1:1 to 1:3 depending on the training goal. Shorter intervals with less rest (1:1 ratio) maximize cardiovascular adaptation and caloric burn. Longer intervals with more rest (1:2 or 1:3) allow for near-maximal power output on each rep, making them better suited for speed and strength development. HIIT has been extensively validated in peer-reviewed research for improving VO₂ max, insulin sensitivity, blood pressure, and body composition in a fraction of the time required by traditional steady-state cardio. It can be applied to virtually any modality — running, cycling, rowing, swimming, calisthenics, or weighted movements — making it the most versatile high-intensity training format available. A typical HIIT session lasts 20–35 minutes including warm-up and cool-down.

Free Online Interval Timer

Zolkit's interval timer runs entirely in your browser — no app to install, no account required. Set any work and rest duration, choose a round count, and start training immediately. Built-in presets cover the most popular protocols: Tabata, HIIT, AMRAP, EMOM, boxing rounds, circuit training, the 7-minute workout, and stretching. Audio cues signal every phase transition so you can keep your eyes on your form, not the screen.

Precise Interval Timing

Accurate to the second with clear audio cues at every work-rest transition. Keeps you focused on training, not clock-watching.

8 Built-In Workout Presets

One-click presets for Tabata, HIIT, AMRAP, EMOM, boxing rounds, circuit training, the 7-minute workout, and stretching — loaded and ready to start.

Fully Customizable Intervals

Set any work duration, rest duration, and round count. Save up to 5 custom presets with your own names for instant access on future sessions.

Audio Phase Cues

Distinct audio tones signal the start of work, the start of rest, and the final round complete. Mute toggle for silent environments.

Works on Any Device

Fully responsive on smartphones, tablets, and desktops. Use it propped up in the gym or on a laptop at home — no installation required.

Completely Free

No subscription, no ads mid-workout, no paywalled presets. All features are available to every user with no account needed.

How to Use the Interval Timer

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Choose a preset workout (Tabata, HIIT, boxing rounds, etc.) or set your own work time, rest time, and round count using the custom fields. Your settings are saved between sessions.
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Click Start. The timer counts down the work interval with a color indicator, then automatically switches to the rest period with an audio cue. Round progress is displayed throughout.
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The timer advances through all rounds automatically. When the final round is complete, a finish sound plays and your total workout is done. Use the Reset button to run it again or adjust your settings.