Forty-five minutes is the length of a school lesson and a strong deep-work block — long enough for real depth before attention naturally fades. This free 45-minute timer runs full-screen in your browser with an alarm and stays accurate in background tabs.
What is a 45 minute timer good for?
- A class period, lecture or tutoring session
- A deep-work or revision block before a break
- A full gym session or long workout
- A long-form reading or writing sprint
How this 45 minute timer works
Press Start and the countdown runs full-screen in your browser; press it again to pause and resume, hit Reset to return to 45 minute, or +1 min to extend. You can also press the spacebar to start or pause. It is wall-clock accurate, so it stays correct even in a background tab, and it rings when it reaches zero. Need a different length or a stopwatch and date countdown? Open the full timer.
Frequently asked questions
Why time a 45-minute block?
Forty-five minutes maps onto how many schools and universities structure a lesson, and it is close to the upper limit of sustained focus for most people before a break sharply improves the quality of the next block. Timing it matters because deep work needs a defined boundary: knowing the session ends at the alarm lets you commit fully without checking the clock, and the hard stop protects the break that keeps the next 45 minutes productive. Start it, remove distractions, and work until it rings.
Does the timer keep accurate time if I switch tabs?
Yes. Instead of counting ticks (which browsers throttle in background tabs), it records the exact end time and works out the remaining time from your clock on every update, so it is always correct. When you return to the tab the display instantly shows the true time left, and the alarm is scheduled through the Web Audio API so it still rings on time even while the tab is hidden.
Will it make a sound when it finishes? Is it free?
Yes to both. When the countdown reaches zero the timer plays an alarm tone and the card flashes with a “Time’s up” message, so you are notified even with the sound off — use the speaker button to mute or unmute. The first time you press Start the browser unlocks audio from that tap, which is why a timer you start yourself can ring later. It is completely free, runs entirely in your browser, needs no sign-up, and nothing is uploaded.