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Warm-upGet ready
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HIIT presets
Load a common work/rest pattern, then fine-tune the timing below.

Interval settings

Set warm-up, work, rest, rounds, cool-down, and optional cues.

Shortcuts: Space start/pause / R reset / N next / F fullscreen

HIIT Timer (Intervals)

Run warm-up, work, rest, rounds, and cool-down intervals with a dominant phase countdown.

How it works

HIIT Timer is built for one job: run clean, repeatable intervals without getting in your way. You set a simple structure warm-up → work/rest rounds → cool-down, then control the session with Start/Pause, Next, and Reset. Presets load common patterns (Tabata, longer intervals, boxing rounds), and fullscreen turns the page into a big, readable training display.

This page is not trying to teach workouts. It is designed to help you run the timing structure clearly and quickly. That means predictable phases, clear round tracking, fast skipping when plans change, and optional sound cues so you do not have to stare at the screen.

If you are setting up a phone on the floor, a laptop on a box, or a TV across the room, the timer display automatically sizes to fit the available space, and fullscreen adds a minimal control bar so you can run the whole session without hunting for buttons.

Warm-upWorkRestRoundsCool-downSound cuesFullscreen
Quick use (what most people do)
  1. 1) Load a preset (Tabata, Intervals, Boxing) or enter your own seconds and rounds.
  2. 2) Decide whether you want Sound and optionally the final 3-2-1 beeps during Work.
  3. 3) Press Start. Warm-up runs once, then Work and Rest repeat for your rounds, then Cool-down finishes the session.
  4. 4) Use Next to skip a phase (skip warm-up, skip a rest, jump to cool-down).
  5. 5) For a clean display, press F to go fullscreen. Exit with Esc.
Total time math (so you know what you are starting)

The session duration is easy to estimate: warm-up + (work + rest) × rounds + cool-down. If Rest is set to 0, the middle becomes work × rounds. This page does not hide that logic. What you enter is what it runs, in that order.

Practical checklist
  • If you want to start immediately, set Warm-up to 0 or press Next.
  • If you do not want rests, set Rest to 0.
  • If you rely on sound cues, press Start once first if your browser blocks audio until interaction.
  • If shortcuts do nothing, click the timer card once so it has focus.
  • If you are running a group, fullscreen keeps controls visible but minimal.
Shortcuts: Space start/pause, N next, R reset, F fullscreen, Esc exit.

What the timer actually runs

There are five possible phases: Warm-up, Work, Rest, Cool-down, and Done. Warm-up and Cool-down run at most once each. Work and Rest repeat based on your Round count, and the Round label tracks progress (for example, Round 3/8).

The behavior is intentionally direct: Next advances to the next phase immediately, and Reset returns you to the start (Warm-up) using your current settings. If you change any of the interval values while not in fullscreen, the session resets to keep the run predictable. You do not want to be mid-round and discover that a new set of values partially applied.

Sound is optional. With Sound on, you get cues at phase boundaries. If you enable final 3-2-1 beeps, the timer adds one beep per second during the last three seconds of Work only. That setting is deliberately limited to Work so it does not turn rests into a constant chirp.

Scenarios with concrete numbers (what you will experience here)

These examples use values you can enter on this page. The total time estimates are simple and match the exact run order.

Scenario 1: Tabata preset (20/10 × 8)
Fast interval block with clear pacing.
Settings: - Warm-up: 0 sec - Work: 20 sec - Rest: 10 sec - Rounds: 8 - Cool-down: 0 sec What you will see: - Phase starts at Work - Round label shows Round 1/8, then 2/8, ... Total time: - (20 + 10) × 8 = 240 sec = 4:00 Helpful controls: - Tap/click the time in fullscreen to start/pause - Press N to skip a rest if you want to keep moving
Scenario 2: Longer intervals (40/20 × 10) plus warm-up/cool-down
A common conditioning pattern when you want more steady work.
Settings: - Warm-up: 30 sec - Work: 40 sec - Rest: 20 sec - Rounds: 10 - Cool-down: 30 sec Total time: - 0:30 + (0:40 + 0:20) × 10 + 0:30 - 0:30 + 1:00 × 10 + 0:30 = 11:00 What you will experience: - One warm-up countdown, then 10 work blocks - Rest blocks are short and predictable
Scenario 3: Boxing rounds preset (3:00 / 1:00 × 6)
Round-based timing with longer work and recovery.
Settings (preset): - Warm-up: 0 sec - Work: 180 sec (3:00) - Rest: 60 sec (1:00) - Rounds: 6 - Cool-down: 0 sec Total time: - (3:00 + 1:00) × 6 = 24:00 On-screen behavior: - Phase chip switches Work ↔ Rest - Round label stays visible the entire time
Scenario 4: No-rest blocks (Rest = 0) for continuous reps
Back-to-back work intervals where you rest off-timer.
Settings: - Warm-up: 30 sec - Work: 45 sec - Rest: 0 sec - Rounds: 12 - Cool-down: 30 sec Total time: - 0:30 + (0:45 × 12) + 0:30 - 0:30 + 9:00 + 0:30 = 10:00 What changes when Rest is 0: - Work repeats immediately between rounds - Next still advances to the next phase (eventually cool-down)
Scenario 5: Group session on a big screen (fullscreen + shortcuts)
You want a clean display and fast control without a mouse.
Suggested workflow: - Press F to enter fullscreen - Press Space to start/pause - Press N to advance to the next phase - Press R to reset to the beginning - Press Esc to exit fullscreen Common setup example: - Warm-up 60 sec, Work 30 sec, Rest 15 sec, Rounds 12, Cool-down 60 sec - Total: 1:00 + (0:30 + 0:15) × 12 + 1:00 = 11:00
Scenario 6: Real-world adjustment mid-session (skip without retyping)
Plans change. This is why Next exists.
Example: you set Warm-up to 60 sec but you are already warm. Option A (before starting): - Set Warm-up to 0 sec Option B (right now): - Press Start, then press N to jump to Work immediately Another example: - You want to end early after the last work block - Press N until you reach Cool-down or Done
Why this page is useful even if you already know your intervals

People often do not need a complicated workout builder. They need a simple timer that runs the same pattern every time and can handle interruptions. This timer is built around that reality: quick presets, visible round tracking, and controls that still make sense when you are out of breath.

If you want a minimal countdown with fewer settings, use Fullscreen Timer. If you want multiple blocks on one screen, use Multiple Timers. If you want strict formats, jump to EMOM Timer or AMRAP Timer.

Related tools (same site, different job)

Pick the closest match to what you are actually trying to do.

Shortcuts: Space N R F Esc
Tabata Timer →EMOM Timer →AMRAP Timer →Round Timer →Workout Timer →Fullscreen Timer →Multiple Timers →
Technical details (timing, sound, focus, fullscreen)
Optional notes if timing behavior matters
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Countdown timing

The timer targets phase endings using a monotonic clock (performance timing) rather than relying only on setInterval. This helps reduce drift if the browser is busy. Visual updates can still stutter on a slow device, but phase transitions aim for the intended durations.

Audio behavior

Web audio may be blocked until a user gesture occurs. If cues are silent, press Start once, then keep Sound enabled. The “final 3-2-1” beeps fire only during Work and only in the last three seconds.

Keyboard focus rules

Shortcuts are handled on the timer card. If they do not work, click the card once to focus it. While typing in a number input, shortcuts are ignored to prevent accidental starts or skips.

Fullscreen targeting

Fullscreen is applied to the timer card itself. That keeps the controls, time display, and phase labels together. Use Esc or the Exit button to leave fullscreen.

Settings changes

Changing warm-up, work, rest, rounds, or cool-down resets the run state back to Warm-up. This prevents confusion where a run continues with a mix of old and new values.

Want a single countdown? Use Countdown Timer for a simple one-shot timer.
Need multiple blocks on screen? Use Multiple Timers for parallel timers.
In one sentence: this HIIT timer runs warm-up, work/rest intervals for a set number of rounds, and cool-down, with presets like Tabata and boxing rounds, optional sound cues, next/reset controls, and fullscreen shortcuts for a clean training display.

Keyboard shortcuts

Click the timer card once, then use the shortcuts below. Shortcuts won’t trigger while you’re typing in an input, select, textarea, or editable field.

KeyAction
SpaceStart / pause
NNext phase
RReset to start
FToggle fullscreen
EscExit fullscreen
Tip: if shortcuts do nothing, the timer card probably isn’t focused. Click the timer once, then try again.

Common scenarios

Use this page to run interval sessions with warm-up, work/rest rounds, and cool-down. Load a preset, tweak durations, then start. You can pause, skip to the next phase, toggle sound cues, and use fullscreen for a clean training view.

Run a Tabata session (20s work / 10s rest × 8)
Load the Tabata preset, optionally set Warm-up/Cool-down to 0, then press Start. Use Next if you want to jump phases without changing settings.
For
Anyone who wants a fast, repeatable Tabata block with clear work/rest cues.
Not for
You need a dedicated Tabata-only page or multiple blocks back-to-back. Use Tabata Timer or Multiple Timers.
Tabata Timer →Multiple Timers →
Standard conditioning intervals (longer work/rest blocks)
Load the Intervals preset (40/20 × 10) or set your own durations. This is the simplest way to run structured intervals without building a full workout plan.
For
People who want predictable interval pacing with easy start/pause and a big, readable display.
Not for
You need time math, schedules, or planning tools. This page is for running the timer.
Workout Timer →Time Calculator →
Boxing / round training (3:00 / 1:00 × 6)
Use the Boxing preset for round-based work. Fullscreen is ideal on a phone or wall display, and sound cues help you move without looking down.
For
Bag work, shadowboxing, sparring drills, or any round-based training.
Not for
You want a minimal bell-only round timer. Use Round Timer.
Round Timer →Fullscreen Timer →
Skip warm-up or cool-down without changing your plan
Set Warm-up or Cool-down to 0 seconds (skip), or use Next to jump forward immediately. This is useful when you’re already warmed up or finishing early.
For
Anyone adjusting on the fly while keeping the rest of the structure intact.
Not for
You need to save named routines. This page focuses on quick setup and run.
Workout Timer →Rest Timer →
No-rest blocks (Rest = 0) for back-to-back work intervals
Set Rest to 0 to run work intervals back-to-back across rounds. You still get clear round counting and an end cue between phases.
For
People doing continuous reps where rest is handled informally off-timer.
Not for
You need an EMOM or AMRAP structure with explicit format rules. Use EMOM or AMRAP Timer.
EMOM Timer →AMRAP Timer →
Hands-free big-screen mode for gyms, classes, or groups
Go fullscreen to maximize readability. Use Space to start/pause, N for next, and R to reset. Keep Sound on if you want phase cues without watching the screen.
For
Small group workouts, classes, or any setup where the timer needs to be seen across a room.
Not for
You need multiple independent timers on one screen. Use Multiple Timers.
Multiple Timers →Presentation Timer →
Quick ‘change of plans’ control during a session
Pause instantly, skip a phase with Next, or reset to the start. This is built for real-world sessions where you might need to adjust without touching settings mid-run.
For
Anyone who wants simple controls while timing a session.
Not for
You want a silent timer only. Use Silent Timer.
Silent Timer →Countdown Timer →
Tip: Press Space to start/pause, N for next, R to reset, F for fullscreen, and Esc to exit fullscreen. If shortcuts do nothing, click the timer card once to focus it.

Frequently Asked Questions

What does this HIIT Timer do?
It runs a structured interval session: warm-up → alternating work/rest rounds → cool-down. You can set seconds and rounds, load quick presets (Tabata, Intervals, Boxing), start/pause, skip to the next phase, reset, toggle sound cues, and use fullscreen with keyboard shortcuts.
What’s the exact phase order?
Warm-up runs once, then the timer alternates Work and Rest for the number of rounds you set, then finishes with Cool-down. If Warm-up or Cool-down is set to 0 seconds, that phase is skipped.
How do rounds work here?
A round is one Work phase (plus an optional Rest phase after it). The round counter shows your current round during Work and Rest. After the final round completes, the timer moves to Cool-down (or completes if Cool-down is 0).
What happens if I set Rest to 0?
Rest is skipped. The timer runs Work back-to-back between rounds, then goes to Cool-down after the final round.
What does Next do?
Next stops the current phase and immediately advances to the next phase in sequence (for example: Warm-up → Work, Work → Rest or the next Work, Rest → next Work, Work (final) → Cool-down).
What does Reset do?
Reset stops the timer and returns you to the start (Warm-up) with your current settings and preset values still in place.
What sound cues are available?
When Sound is enabled, you’ll get a short cue at the end of each phase. If you enable Final 3-2-1 beeps, the timer also beeps once per second in the last 3 seconds of Work only.
Why might I not hear sound cues?
Some browsers block audio until you interact with the page. If cues are silent, click/tap Start once (a user gesture), then keep Sound on and try again. Also make sure your device is not muted and your volume is up.
Does fullscreen change how controls work?
Fullscreen gives you a clean, large display with a top bar (Start/Pause, Next, Reset). You can also tap/click the timer display to start or pause. Exit fullscreen with Esc.
What keyboard shortcuts are supported?
Space starts/pauses, R resets, N advances to the next phase, F toggles fullscreen, and Esc exits fullscreen. Shortcuts are ignored while you are typing in an input.
Which related timer should I use instead?
Want Tabata without warm-up/cool-down controls? Tabata Timer. Need EMOM or AMRAP formats? EMOM Timer or AMRAP Timer. Prefer a simple round bell timer? Round Timer. Want a no-frills big display? Fullscreen Timer. Need multiple timers at once? Multiple Timers.

HIIT Timer at a glance

Warm-up • Work • Rest • Rounds • Cool-down • Tabata preset • Boxing preset • Sound cues • Next/Reset • Fullscreen + shortcuts

▼
Use this page to run repeatable intervals with a simple structure: warm-up → work/rest rounds → cool-down. Load a preset, tweak seconds and rounds, then start. You can pause, skip to the next phase, reset, and run it fullscreen with keyboard shortcuts.
Flexible interval setup. Set warm-up, work, rest, rounds, and cool-down. Use 0 seconds to skip warm-up or cool-down, or to run no rest.
Quick presets. Start fast with Tabata 20/10 × 8, Intervals 40/20 × 10, or Boxing 3:00/1:00 × 6, then adjust if needed.
Start, pause, next, reset. Pause any time, jump to the next phase with Next, or Reset back to warm-up.
Sound cues (optional). Toggle Sound on/off. Optionally enable final 3-2-1 beeps during work only.
Fullscreen training view. Go fullscreen for a clean, big display with top controls. In fullscreen, you can tap/click the time to start or pause. Exit with Esc.
Large, readable timer. The time display auto-sizes to fit your screen, so it stays readable on phones, laptops, and wall displays.
Quick use
  1. 1) Load or set: pick a preset or set seconds/rounds manually.
  2. 2) Choose cues: turn on Sound (optional) and final 3-2-1 beeps (work only).
  3. 3) Run it: press Start. Use Next to skip a phase or Reset to restart.
Common setups
  • Tabata: 20s work / 10s rest × 8 rounds (warm-up/cool-down optional).
  • Intervals: longer work/rest for conditioning (example preset: 40/20 × 10).
  • Rounds (boxing): 3:00 work / 1:00 rest × 6 rounds.
  • No-rest EMOM-style: set Rest to 0 and use Rounds to control total reps.
Related tools
Want a dedicated Tabata page? Tabata Timer.
Need EMOM or AMRAP formats? EMOM Timer or AMRAP Timer.
Prefer a simple round bell timer? Round Timer.
Want fewer controls and a big screen? Fullscreen Timer.
Looking for a general workout tool set? Workout Timer.
Controls + behavior details▼
Keyboard shortcuts

Space start/pause · N next · R reset · F fullscreen · Esc exit fullscreen.

Shortcuts are ignored while typing in inputs.

Phase flow

Warm-up runs once, then the timer alternates Work and Rest for your selected number of rounds, then ends with cool-down.

If Rest is 0, the timer goes work → work between rounds.

“Next” behavior

Next stops the current phase and immediately advances to the next phase in the sequence. Use it to skip warm-up, skip a rest, or jump into cool-down.

Sound notes

Some browsers require a user gesture before audio will play. If you do not hear cues, press Start once, then enable Sound and try again.

Final 3-2-1 beeps trigger in the last 3 seconds of work only.

Tip. For a hands-free setup: go fullscreen, keep Sound on, and use Space to start/pause and N to skip to the next phase when you need it.

Other interval workouts