logo Toolmaxy
New Popular

Nanosecond Timer

High-precision online stopwatch with nanosecond accuracy. Lap times, split times, and copy results.

00:00:00 .000 000
Ready

Keyboard: Space Start/Stop  ·  L Lap  ·  R Reset

What Is a Nanosecond Timer?

A nanosecond timer is a high-precision stopwatch that measures elapsed time with sub-millisecond accuracy. This tool uses the browser's Performance API (performance.now()), which provides timestamps accurate to 5 microseconds (5,000 nanoseconds) in most modern browsers - far more precise than the standard Date.now() which only has millisecond resolution.

The display shows time broken down into hours, minutes, seconds, milliseconds, and microseconds. While browsers intentionally limit precision to prevent timing-based security attacks (Spectre/Meltdown), the available precision is more than sufficient for benchmarking code execution, measuring reaction times, timing experiments, and performance testing.

The lap feature records both the individual lap duration and the cumulative split time at each lap. In Full Screen mode, the tool expands to fill your entire display, providing a high-visibility interface ideal for presentations or laboratory environments. The table automatically manages its height in full screen, ensuring the timer remains perfectly centered.

Customize your experience with the Light/Dark Mode toggle. Whether you prefer a focused dark interface or a clean light workspace, the tool adapts instantly while maintaining high contrast for the nanosecond-precision numbers.

Use keyboard shortcuts for hands-free operation: Space to start/stop, L to record a lap, and R to reset.

Timer Precision by Browser

Browser Precision Notes
Chrome / Edge ~5 μs (5,000 ns) Best precision available in browsers
Firefox ~1 ms (1,000,000 ns) Reduced by default for security
Safari ~1 ms (1,000,000 ns) Reduced for privacy protection
Node.js ~1 ns Use process.hrtime.bigint() for true nanoseconds

Frequently Asked Questions

How accurate is this nanosecond timer?

The timer uses the browser's Performance API (performance.now()), which provides sub-millisecond precision — typically accurate to 5 microseconds (5,000 nanoseconds) in most browsers. True nanosecond hardware precision requires OS-level access, but this is the highest precision available in a web browser.

What is the difference between a lap and a split?

A lap time shows the duration of each individual interval (time since the last lap). A split time shows the total elapsed time at the moment you pressed the lap button. Both are recorded simultaneously for each lap.

What are the keyboard shortcuts?

Space bar: Start/Stop the timer. L key: Record a lap. R key: Reset the timer. These shortcuts work when the timer area is focused.

Can I copy the results?

Yes. Click "Copy Results" to copy all lap times and the total elapsed time to your clipboard in a formatted text table.

Why does the browser limit timer precision?

Browsers intentionally reduce timer precision to mitigate Spectre/Meltdown timing attacks. Firefox reduces precision to 1ms by default; Chrome provides ~5μs precision. For true nanosecond measurements, use system-level tools like perf (Linux) or Windows Performance Toolkit.

What is performance.now()?

performance.now() is a Web API that returns a high-resolution timestamp in milliseconds (with fractional microseconds) relative to the page load time. It's more precise than Date.now() and is not affected by system clock adjustments.

More Developer Tools

View all