What is the Tabata protocol?

A landmark HIIT protocol published by Dr. Izumi Tabata in 1996: 20 seconds of all-out work + 10 seconds rest, repeated for 8 sets (4 minutes total). It is shown to improve both aerobic and anaerobic capacity in a short time and is widely used worldwide. Apply it instantly via the 'Tabata' preset.

How does HIIT differ from Tabata?

HIIT (High-Intensity Interval Training) is the broad umbrella of alternating high-intensity bursts with short rests. Tabata is one specific HIIT protocol (20/10 × 8). Common HIIT patterns include 30/30, 40/20, 45/15, 60/30 etc., chosen by goals and fitness level. Use the presets or set any values manually.

Does it remember timer state across tabs?

Settings (warm-up / work / rest / cool-down / rounds / audio toggles) are saved to localStorage, but the *running* state (elapsed time, current phase) is **not** persisted. Closing or reloading the tab restarts from idle.

How does the audio work?

Short beeps are synthesised in-browser with the Web Audio API — no external audio files. Work-start uses high tones (880 → 1320 Hz), rest-start lower ones (440 → 330 Hz), warm-up ascends (523 → 659 Hz), cool-down descends (659 → 523 Hz), finished plays a C-major chord (523 → 659 → 784 → 1047 Hz). The final-3-seconds tick is a short square pulse (1200 Hz). Browsers require a user gesture before audio works, so the AudioContext is unlocked on the first Start click.

Does it stay accurate in background tabs?

Phase transitions use `performance.now()` deltas, so they remain accurate even when setInterval is throttled. However, some browsers mute audio in background tabs — keep this tab in the foreground during workouts.

Warm-up / cool-down / rest: 0–600 sec (= 10 min). Work: 1–600 sec. Rounds: 1–99. Phases set to 0 sec (e.g., warm-up or cool-down) are skipped automatically.

Is anything uploaded?

No. Timer logic, settings and audio synthesis all run inside your browser; nothing is sent over the network.

Back to Time

Interval Timer (HIIT / Tabata work / rest round manager)

A browser-only interval timer for HIIT (High-Intensity Interval Training) and Tabata (20 s work / 10 s rest × 8 rounds). Configure warm-up, work, rest, cool-down and rounds in seconds, with the current phase / remaining time / round progress shown live. Settings autosave to localStorage. Phase transitions trigger short Web Audio beeps (work start = high 880 Hz, rest start = low 440 Hz, finished = chord), and the final 3 seconds add an optional countdown tick. One-click presets: Tabata (20/10 × 8), HIIT 30/30, HIIT 45/15, HIIT 40/20. Uses `performance.now()` deltas so transitions stay accurate in throttled background tabs. Timer logic and audio all run inside your browser — nothing is uploaded.

timecalculatorgenerate

How to use

1) Pick a preset (Tabata / HIIT 30-30 / HIIT 45-15 / HIIT 40-20) or manually set warm-up / work / rest / cool-down (seconds) and rounds. Settings autosave to localStorage. 2) Press Start — the warm-up phase (if any) begins, then work → rest alternates for the configured rounds. A cool-down (if any) follows the final round. 3) Phase changes trigger short Web Audio beeps (work = high, rest = low, finished = chord) and the optional final-3-seconds tick. 4) Pause, Reset and Skip work mid-session. Phases set to 0 seconds are skipped automatically.

FAQ

What is the Tabata protocol?: A landmark HIIT protocol published by Dr. Izumi Tabata in 1996: 20 seconds of all-out work + 10 seconds rest, repeated for 8 sets (4 minutes total). It is shown to improve both aerobic and anaerobic capacity in a short time and is widely used worldwide. Apply it instantly via the 'Tabata' preset.
How does HIIT differ from Tabata?: HIIT (High-Intensity Interval Training) is the broad umbrella of alternating high-intensity bursts with short rests. Tabata is one specific HIIT protocol (20/10 × 8). Common HIIT patterns include 30/30, 40/20, 45/15, 60/30 etc., chosen by goals and fitness level. Use the presets or set any values manually.
Does it remember timer state across tabs?: Settings (warm-up / work / rest / cool-down / rounds / audio toggles) are saved to localStorage, but the *running* state (elapsed time, current phase) is **not** persisted. Closing or reloading the tab restarts from idle.
How does the audio work?: Short beeps are synthesised in-browser with the Web Audio API — no external audio files. Work-start uses high tones (880 → 1320 Hz), rest-start lower ones (440 → 330 Hz), warm-up ascends (523 → 659 Hz), cool-down descends (659 → 523 Hz), finished plays a C-major chord (523 → 659 → 784 → 1047 Hz). The final-3-seconds tick is a short square pulse (1200 Hz). Browsers require a user gesture before audio works, so the AudioContext is unlocked on the first Start click.
Does it stay accurate in background tabs?: Phase transitions use `performance.now()` deltas, so they remain accurate even when setInterval is throttled. However, some browsers mute audio in background tabs — keep this tab in the foreground during workouts.
What are the limits?: Warm-up / cool-down / rest: 0–600 sec (= 10 min). Work: 1–600 sec. Rounds: 1–99. Phases set to 0 sec (e.g., warm-up or cool-down) are skipped automatically.
Is anything uploaded?: No. Timer logic, settings and audio synthesis all run inside your browser; nothing is sent over the network.

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