Audio latency test
Press Start to create an audio context and read its reported base and output latency. For a rough measure of the whole delay, tap along to eight beeps. Because your own timing is part of the tap result, treat it as an estimate.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Press Start to read the reported latency of your browser’s audio system.
- Press Start tap-along, then tap the button or press Space as you hear each of the eight beeps.
- Read the mean and median offset. Press Stop to close the audio context.
How it works
The beeps are scheduled on the audio clock. Their audible time is converted to the page clock with getOutputTimestamp where available. Each tap is compared with the nearest beep, and taps farther than 300 ms from any beep are ignored.
Worked example
Beeps at 0, 600 and 1200 ms and taps at 20, 590 and 1250 ms give offsets of +20, -10 and +50 ms. The mean is 20 ms and the median is 20 ms.
Tips
- Run the test with wired speakers first, then with Bluetooth, and compare.
- Close other audio apps; they can change the system latency.
Frequently asked questions
What do baseLatency and outputLatency mean?
Base latency is the processing delay inside the browser's audio system. Output latency is the extra delay until sound leaves the device, if the browser reports it. Not every browser provides output latency.
Why does Bluetooth feel slower than the numbers?
Wireless audio adds delay in the headphones and radio link, often well over 100 ms, and the browser usually cannot see it. The tap-along measures the whole path, including that delay.
How accurate is the tap-along?
It is only an estimate. Your own reaction time and rhythm habits are mixed into the number, so use it to compare setups, like speakers against Bluetooth headphones, and repeat a few times.
Does the test record my audio or use the microphone?
No. It only plays beeps through your output device. No microphone permission is requested.