Online Stopwatch: Free Stopwatch with Lap Timer | Precise Timing

A You can control the stopwatch without touching your mouse. Press 'S' to start or stop the timer. Hit 'L' to record a lap. And 'R' resets the whole thing. These shortcuts make timing events much quicker for things like sprints or kitchen timers.

A They vanish. This stopwatch runs entirely in your browser's memory, not on a server. No data gets saved when you close the tab or refresh the page. If you need to keep records, write them down or take a screenshot before navigating away. For a 5K race, I'd jot down splits between laps.

A That's not a glitch, it's centisecond precision at work. The timer counts in 1/100th second increments, so it hits 0.99 before rolling over to 1.00. This gives you finer granularity than a standard stopwatch that only shows tenths. For sprint timing or reaction tests, that extra digit matters. If you're measuring something like a 30-second plank, the hundredths won't change your results much.

A Yes, it keeps ticking in the background. Most browsers let JavaScript timers continue running even when the tab isn't active. I've tested this on Chrome and Safari—switching tabs for 20 seconds and coming back showed the correct elapsed time. But some mobile browsers might throttle the timer after a minute or two. If you're timing a long workout, keep the tab visible. For quick tasks like boiling pasta, tab switching won't be an issue.

A No, this tool runs one stopwatch per browser tab. For multiple simultaneous timers, open separate tabs or windows — each one works independently. Teachers timing different student presentations might prefer a dedicated multi-timer app, but for most tasks like tracking parallel cooking steps, two browser tabs side by side does the job fine.

A Yes, it runs for days if you leave it. I've let it tick past 72 hours during a weekend hackathon to track total coding time. The centisecond precision drops after the first hour — laps show hours:minutes:seconds, not hundredths. For anything longer than a few hours, focus on lap splits instead of staring at the total. If you're counting days to a vacation, this isn't the right tool; use a countdown app instead.

A Yes, you get both at once. The main timer shows total elapsed time from when you first hit Start. Below that, the lap list records each split. So if you're timing a 5K run, the main display shows your overall race time while the lap entries show each kilometer's split. The fastest lap gets highlighted automatically. For coaches tracking interval training, this dual view means no mental math. Just watch the main timer for rest periods and check lap details for performance.

A Yes, but you can undo it. If you hit the Start/Stop button when you meant to press Lap, the whole timer pauses. No panic — just hit Start again and your previous laps stay intact. The paused time will be added onto your total, though. For example, if you paused for 3 seconds during a 400m sprint, that pause gets baked into your final time. Best practice: remap your grip so your thumb finds the Lap key, not Stop.

A That's just a zero-length split, not a bug. If you hit Lap within the same centisecond the timer started, the elapsed time rounds to 0.00. Wait a couple of seconds before your first lap to get a meaningful reading. For a sprint reaction test, this can actually be useful—it tells you exactly how fast you clicked. But for tracking real intervals, give the timer a moment to accumulate time before pressing Lap.

A Yes. Look for the fullscreen icon in the corner, or press 'F' on your keyboard. It blacks out the rest of the page so students or meeting attendees only see the timer. For a 45-minute lecture or a 15-minute client pitch, this makes the countdown unmissable. I've even used it during a contract negotiation to track speaking time without anyone noticing the tool. One catch: the lap list hides in fullscreen, so record splits before you expand.