Audio latency test

What this test measures — and what it doesn't

The test reads the two latency figures your browser's audio engine reports: base latency, the buffer the browser holds internally, and output latency, the browser's estimate of the time between handing a sample to the operating system and it leaving the speaker. Added together, they are the floor of your system's audio delay.

They are a floor, not a total. Not included: the Bluetooth link (typically 100–200 ms), any delay in the microphone path, processing inside a meeting app, display buffering, and network transit on a call. A machine reporting 12 ms here can still have 250 ms of real end-to-end delay on a wireless headset.

Interpreting your number

Useful reference points: about 20–30 ms is where most people begin to notice audio trailing video; roughly 10 ms is the threshold at which musicians find live monitoring unplayable; and standard Bluetooth adds far more than either figure, which is why wireless earbuds are unsuitable for recording.

Why the number differs between browsers

Run the test in two browsers on the same machine and you will usually get two different answers. That is expected:

• Chrome and Edge report both base and output latency, so their totals tend to be the most complete — and therefore the highest-looking.
• Firefox reports base latency reliably but output latency inconsistently across platforms.
• Safari historically exposes little or nothing, in which case this test falls back to estimating from the audio quantum (128 samples) and your sample rate. That estimate is optimistic — it is the theoretical minimum, not what you experience.

Because of this, compare the same browser across configurations rather than comparing browsers against each other.

How to lower audio latency

In roughly descending order of effect:

1. Use a cable. Removing Bluetooth is worth more than every other change on this list combined — often 100 ms or more.
2. Plug in directly. USB hubs, docks, and monitor audio outputs all add buffering.
3. Close the competition. Other applications holding the audio device force the system into safer, larger buffers.
4. Use a proper driver. On Windows, ASIO for an audio interface bypasses the shared Windows mixer entirely. On macOS, Core Audio is already low-latency; avoid aggregate devices unless you need them.
5. Disable audio "enhancements". Spatial audio, virtual surround, and vendor DSP each insert processing delay.
6. Match sample rates. If the OS runs at 48 kHz and the application at 44.1 kHz, a resampler sits in the path adding both delay and CPU load.
7. Plug the laptop in. Power-saving modes raise buffer sizes to reduce CPU wake-ups.

The full explanation of where each millisecond comes from is in audio latency explained.

Latency, lip-sync, and echo on calls

Three common complaints trace back to delay, but each has a different cause:

• Video is ahead of audio. Almost always Bluetooth headphones. Switch to wired and it disappears.
• Everyone hears themselves echoed back through you. Your speaker output is being picked up by your microphone, and delay is what turns that feedback into a distinct echo instead of a hum. Headphones fix it instantly; echo cancellation only manages it.
• People talk over each other constantly. Round-trip delay above roughly 300 ms breaks the natural turn-taking rhythm of conversation. That is mostly network, not your hardware — check connection quality before blaming the headset.

If you are chasing an echo specifically, run the recorder: an echo that shows up in your own local recording is a room-and-microphone problem, while one that only others hear is a routing problem.

Frequently asked questions