多计时器

One screen, up to six independent clocks

This tool is a multi-timer board: you can run as many as six separate timers at once, and each one is fully independent. Any timer can be switched between two modes — countdown (counts down from a target you set and alerts you at zero) or stopwatch (counts up from zero with lap recording). That mix is the whole point. While a 12-minute countdown ticks away for the pasta, a second countdown watches the oven, and a stopwatch tracks how long the whole meal is taking — all visible side by side, each with its own name and colour.

How the timing stays accurate

Naive timers that just add "one second" on every setInterval tick drift, because the browser never fires intervals at perfectly even spacing. This tool avoids that. It runs a single animation loop and, on every frame, measures the actual elapsed milliseconds since the previous frame using performance.now(), a high-resolution clock. That real delta is subtracted from a countdown's remaining time or added to a stopwatch's elapsed time. Because the math is based on measured wall-clock differences rather than counted ticks, the displayed time stays faithful even if a frame is briefly delayed. The countdown display shows hours, minutes and seconds; the stopwatch additionally shows centiseconds (hundredths) for precise lap timing.

A worked example: a 5-minute countdown

Add a timer and it defaults to countdown mode with a target of 00:05:00 — five minutes. The circular ring around the digits is a progress indicator: it's drawn as an SVG circle whose visible arc grows as time passes. Concretely, the tool computes progress as 1 − (remaining ÷ target), so at the halfway point — 2 minutes 30 seconds left — the ring is exactly half filled. Press Start and the digits count down. When they reach zero the timer stops itself, the card pulses, a four-note chime plays (a rising C–E–G–C arpeggio synthesised with the Web Audio API), and "Time's up!" appears. The Start button becomes Restart, which resets it to the full target.

Setting custom durations and using stopwatch laps

To change a countdown's length, type into the Target field using HH:MM:SS format — for example 00:25:00 for a 25-minute focus block, or 01:30:00 for a 90-minute exam. You can only edit the target while the timer is stopped; once it's running the field locks to prevent accidental changes. Switch a timer to stopwatch mode and a Lap button appears. Each tap records the current elapsed time as a numbered lap in a scrolling list below, which is ideal for timing repeated efforts — interval running, multiple speech rehearsals, or comparing how long each step of a process takes.

Desktop notifications when you're on another tab

The first time you add a timer, the browser asks permission to show notifications. Grant it, and when a countdown finishes while you're working in a different tab or application, a system notification pops up reading "[timer name] finished!" — so a timer minimised in the background still reaches you. If you decline the permission, the in-page chime and visual pulse still fire; you just won't get the OS-level alert. The audio is generated live in your browser, so no sound file is downloaded and nothing about your timers is sent anywhere.

Practical use cases

• The Pomodoro technique. Set one countdown to 25 minutes for focused work and a second to 5 minutes for the break; name them and give them contrasting colours so a glance tells you which phase you're in.
• Cooking several dishes. A separate, clearly named countdown per pan means nothing gets forgotten, and the chime tells you which one finished.
• Workout intervals. Use a stopwatch with laps to record each set, or a short countdown for timed rest periods.
• Tracking billable or study blocks. Run a stopwatch in the background to measure exactly how long a task actually took.

Things to keep in mind

• Timers don't persist. They live only in the open page. Reloading or closing the tab clears everything, so don't refresh mid-countdown.
• Keep the tab from fully sleeping. Some browsers heavily throttle background tabs to save power, which can slow updates while you're away — the notification still fires on completion, but for critical timing keep the tab reasonably active.
• Enable sound for the chime. If your device is muted or the tab is muted, the audio alert won't be audible; rely on the visual pulse and the desktop notification in that case.
• The six-timer cap is deliberate. Once you reach six, the Add button stops adding — remove one with the ✕ to free a slot.