Online Stopwatch: Free Stopwatch with Lap Timer | Precise Timing

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.

A It can, especially on laptops and phones. The timer forces your screen to stay awake and the display updates every centisecond, which keeps the processor lightly active. On a typical phone, an hour of running time might drain 15 to 20 percent of battery. Lower your screen brightness or close other heavy apps to stretch it out. For a long session, like tracking a 3‑hour exam, plug in the charger. That simple step avoids a dead device right when you need the final number.

A Press the Spacebar to start and stop the timer instantly. This saves you from hunting for buttons with a mouse during a fast-paced kitchen recipe or workout session. Hitting the Enter key records a new lap without interrupting the flow. I use these shortcuts daily when timing language study blocks. Make sure your browser window is active first.

A Yes, clearing your cache or closing the tab wipes out all recorded split data instantly. The timer doesn't save sessions to cloud storage or local cookies because it's built to run locally in your memory. If you're tracking a 10-item inventory count or a complex recipe, don't close that tab by accident. Copy your lap times to a notes app before shutting down your browser. Exporting isn't automated yet.

A Yes, power-saving sleep states freeze browser memory and drop active timers. Your Windows or Mac laptop will suspend the JavaScript thread when the lid closes. I learned this the hard way during a 2-hour baking test when my screen went dark. Unsaved lap splits vanished completely. Adjust your power settings to keep the display awake before you start timing long sessions.