Does the 45 second timer work accurately in background tabs?

Yes. TimerBox uses millisecond-accurate timestamp offsets via Date.now(), so your 45 second countdown never loses a tick if you switch applications or tabs.

Will an audible chime sound when the 45 seconds finish?

Yes. As soon as the timer reaches zero, an audible chime synthesized via the Web Audio API will play.

Can I expand this 45 second timer to fullscreen?

Yes. Tap the fullscreen button or press "F" on your keyboard to view giant countdown digits across your screen.

Is this second timer completely free with no account?

Yes. TimerBox is 100% free with no sign-up, no downloads, and no ads.

45 Second Timer

00:45

Free Online 45 Second Timer Countdown

•Free 45 Second Timer•45s Countdown with Alarm•Background Tab Accuracy•Instant Millisecond Clock

Accurate 45 Second Countdown Timer

Need a fast 45 second timer for high-intensity intervals, kitchen steeping, classroom games, or quick reaction drills? TimerBox provides an instant countdown with audible chime alerts and fullscreen mode that begins the exact millisecond you click Start or press spacebar.

Running locally in your browser with Date.now() timestamp calculations, this timer guarantees zero drift and background tab precision across desktop, tablet, and mobile.

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1 – 10 Minutes

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10 Minute Timer

11 – 20 Minutes

11 Minute Timer
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21 – 40 Minutes

21 Minute Timer
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45 – 120 Minutes

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45 Minute Timer
50 Minute Timer
55 Minute Timer
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90 Minute Timer
2 Hour Timer

Start Your 45 Second Countdown Now

No accounts. No sign-up. Just hit Start or tap your spacebar to begin counting down.