Audio Latency Test: Check Bluetooth & Headphone Delay
Click Start Test on this audio latency test and tap I Heard It! to get your Estimated Latency Range. Nothing you do in the check your hearing range ever leaves your device — the whole test runs locally in your browser tab.
Ever noticed footsteps in a game arriving a beat after you see them? This Bluetooth audio latency test shows how much delay your wireless or wired headphones add, measured in milliseconds. You tap when the screen flashes, tap again on a beep, and the gap between the two tells you whether your sound and picture stay in sync.
How This Audio Latency Test Measures Your Delay
A latency test in the browser can't see inside your headphones, so it uses your own timing as the probe. It measures relative latency: the time added between the moment the page plays a sound and the moment you react to it, which approximates your end-to-end audio output latency. It isn't lab-grade, but it is good enough to measure audio latency differences between devices. Nothing you do in the test speaker frequency range ever leaves your device — the whole test runs locally in your browser tab.
Calibrate Your Reaction Time
Calibration comes first. The screen flashes several times and you tap each time you see it. Those taps record your visual reaction time, the baseline the test later removes so that only the audio part is left. Sit in a quiet room, watch the display with your peripheral vision rather than staring at one spot, and keep your finger resting on the key. Rounds that stand out as outliers are dropped, and the accuracy figure shows how consistent the rest were.
Tap on the Beep, Then Read Your Result
Next, a beep plays through your earbuds or headphones and you tap the moment you hear it. You can also click instead of pressing a key. Each tap now contains your reaction plus the playback delay. Some latency tester tools instead play steady beats at a fixed bpm and keep a trailing average of how far your taps land behind them, or let you drag a slider until a flash and a click feel simultaneous. All three approaches estimate the same delay.
Worked Example: Bluetooth Audio Latency in Milliseconds
The result is simply the difference between your two averages:
$$\text{Latency} = \overline{t}_{\text{beep}} - \overline{t}_{\text{flash}}$$
Say you test a pair of Bluetooth headphones over five rounds of each phase:
- Flash taps: 231, 244, 226, 238 and 249 ms, an average of 237.6 ms
- Beep taps: 412, 398, 425, 404 and 419 ms, an average of 411.6 ms
\(411.6 - 237.6 = 174\) ms of audio latency. Run the same test on wired headphones and get 19 ms, and the Bluetooth link alone accounts for \(174 - 19 = 155\) ms, typical of a standard codec.
Typical Headphone Delay by Codec and Connection
Your headphone delay depends mostly on the connection and the Bluetooth codec both ends agree on. These are the usual ranges: Nothing you do in the microphone quality and spectrum analyzer ever leaves your device — the whole test runs locally in your browser tab.
| Connection or codec | Typical delay | Comfortable for |
|---|---|---|
| Wired headphones or speakers | 5-20 ms | Live instruments and everything else |
| aptX Adaptive or LE Audio | 40-80 ms | Gaming and video |
| Classic aptX | 60-120 ms | Video and casual gaming |
| AAC (most earbuds) | 100-200 ms | Music and most video |
| SBC (older Bluetooth) | 150-300 ms | Music listening only |
Testing speakers? Your result then also includes air travel from the sound source, about 3 ms per metre, so sit where you normally listen.
Why Wireless Delay Is Higher on Bluetooth Headphones
Wireless delay builds up along the whole chain. The app hands audio to the operating system's audio stack, which passes it to the radio. There it is encoded, split into packets for transmission, buffered so radio interference doesn't cause gaps, then decoded inside the headphones before the DAC and headphone driver turn it back into sound. Every stage holds a few milliseconds. Wireless headphones add the extra buffering that a cable never needs, which is why the same hardware can measure very differently wired and unwired. Newer Bluetooth gear helps only when both ends support the faster codec.
Acceptable Output Latency for Video Calls and Music Production
How much output latency you can live with depends on what you're doing:
- Competitive gaming: under about 40 ms, so sound cues like footsteps match the action
- Video calls, video editing and watching movies: lip-sync errors start to show near 80-100 ms
- Music listening: even 200 ms is fine, since nothing needs to line up
- Music production, singing and live performance through monitors or in-ear monitors: under 20 ms
Real-time monitoring is the strictest case, because a delay you can hear throws off your timing.
Finding a Rhythm Game Offset by Measuring Wireless Delay
I've just paired new noise-cancelling earbuds to a laptop and want to play osu! on the train. The question is narrow: can I keep playing at Overall Difficulty 8, or do the earbuds force me back to wired? At OD 8 the window for a perfect hit is \(80 - 6 \times 8 = 32\) ms either side of the note, so any delay I don't correct pushes good taps toward the edge of that window. Before deciding, I time the earbuds' playback delay with the test on this page. Short answer: with the earbuds' game mode on, the delay is 91 ms, which the game's offset setting can absorb.
I run the calibration first with the space bar, because that's the key I'll actually press: flash taps of 263, 248, 271, 255 and 259 ms, a 259.2 ms average. Then the beep phase in the default mode: 448, 431, 462, 439 and 454 ms, a 446.8 ms average. The difference, my Bluetooth output latency, is 187.6 ms. I check it by hand from the five pairs of numbers and get the same figure.
Then I change one thing, switch on game mode in the earbuds' app, and rerun only the beep phase:
| Earbud mode | Average beep tap | Measured delay |
|---|---|---|
| Default | 446.8 ms | 187.6 ms |
| Game mode | 350.4 ms | 91.2 ms |
Game mode cuts the delay roughly in half, and 91 ms is a value I can type straight into the game's universal offset (as −91 ms), after which my taps should land inside the 32 ms window again.
The figure I'd watch most closely is the noise, not the mean. My flash taps have a spread of about 9 ms and the game-mode beep taps about 10 ms, so with five taps each the difference carries roughly ±11 ms of uncertainty at 95% confidence. That is a third of the hit window, so I treat 91 ms as a starting point and then fine-tune with the game's own offset wizard, which uses the game's audio path rather than the browser's. One caveat a quick search won't tell you: some earbuds silently drop out of game mode after a reconnect, so if timing suddenly feels late again, rerun the beep phase before blaming your hands.
How to Reduce Audio Delay and Measure Latency Accurately
Once a Bluetooth latency test shows a high number, a few changes cut the audio delay, and a few habits make the next reading of your audio output latency more reliable.
Gaming Mode, Low Latency Mode and aptX Low Latency
- Turn on gaming mode or low latency mode in your headphone app
- Pick aptX Low Latency or aptX Adaptive when your phone or PC supports it
- Keep the headphones charged and stay close to the transmitter
For a TV, soundbar or projector, use the AV sync or lip-sync setting to delay the picture by your measured sound delay.
Round-Trip Latency, Buffer Size and Sampling Rate
The test above measures one-way playback delay; when you record through an audio interface, measure round-trip latency instead. Connect your sound card's output to its input with a loopback cable, play a sine sweep in full-duplex mode and find the delay by cross-correlation. The figure covers A/D and D/A conversion, audio drivers and any algorithmic latency, so it is the floor; adding a loudspeaker and microphone only adds time. Smaller buffer size values (fewer samples per frame) and a higher sampling rate lower it:
$$\text{Latency (ms)} = \frac{1000 \times \text{samples}}{\text{sample rate}}$$
A 480-sample ASIO buffer at 48 kHz is 10 ms. Use ASIO or WASAPI on Windows and CoreAudio on macOS, close other programs and check for dropouts or underruns before trusting a reading.
Browser Readings: Web Audio API outputLatency and baseLatency
Browsers also report two estimates through the Web Audio API: baseLatency, the browser's own processing buffer, and outputLatency, the path through the system to the hardware. Neither can see inside Bluetooth headphones, so the tap result usually reads higher on wireless devices.
Frequently Asked Questions
- What is audio latency?
- Audio latency is the time between a device starting to play a sound and that sound reaching your ears. It builds up across the app, the operating system's audio stack, the DAC or Bluetooth link, and the headphone driver. Wired outputs usually add 5-20 ms, while Bluetooth can add 40 ms to 300 ms depending on the codec.
- How does this audio latency test work?
- First you tap whenever the screen flashes, which records your visual reaction time. Then you tap whenever you hear a beep, which records reaction time plus playback delay. Subtracting the flash average from the beep average leaves the delay your headphones or speakers add.
- How much audio latency is acceptable?
- It depends on the task. Under 40 ms suits competitive gaming and music production, 40-80 ms is fine for casual gaming and video calls, lip-sync slips become noticeable around 80-100 ms, and plain music listening tolerates 200 ms because nothing has to line up.
- Why is Bluetooth latency so much higher than wired?
- Bluetooth audio has to be encoded, sent in packets, buffered against radio interference and decoded in the headphones. The codec matters most: SBC and AAC are slow, aptX is faster, and aptX Adaptive or LE Audio can come close to 40-80 ms when both devices support them.
- How can I reduce Bluetooth audio delay?
- Turn on gaming or low latency mode in your headphone app, use aptX Low Latency or aptX Adaptive if your phone or PC supports it, keep the headphones charged and close to the source, and switch to wired headphones for competitive play.
- How accurate is a tap-based latency test?
- It is an estimate, not a lab measurement, because each tap varies by several milliseconds. Use a quiet room, tap with the same key every time, and run the test two or three times. Testing once on wired headphones gives a baseline to subtract from your Bluetooth result.
- What is the modulo between beats?
- When you tap along to a beat, a very late tap can look like an early tap on the next beat. The modulo divides your latency by the time between beats and keeps the remainder, which shows the delay you'd get if you missed the first beat. Ideally it equals your measured latency.