Input Lag Test - Free Online Input Lag Tester

For competitive gaming, a total system input lag of under 20ms is considered excellent and gives you responsive, precise control in fast-paced titles like CS2, Valorant, and fighting games. Input lag between 20 and 40ms is acceptable for most players, including competitive players in less timing-critical games. Latency above 40ms becomes noticeable as a perceptible delay in all action games and is a significant disadvantage in any competitive setting. Wired USB controllers and keyboards typically achieve 1 to 8ms of hardware input lag, while wireless connections add 4 to 12ms on top of that.

Use the Input Lag Tester on this page. Select your input device (controller, keyboard, mouse, or touch), select your connection type, then click Start Test. A visual cue will appear after a random delay — react as quickly as possible by pressing a button. The tool uses high-precision browser timestamps to calculate the delay between the visual cue appearing and your input registering. Run at least 10 rounds and use the average result. Compare your average across wired and wireless connections to isolate how much latency your connection type adds versus your baseline human reaction time.

Wired USB is consistently faster than wireless for input lag. A wired controller reduces connection latency to under 2ms. Bluetooth typically adds 4 to 12ms of latency from signal encoding, wireless transmission, and Bluetooth stack processing. Proprietary 2.4GHz wireless protocols like Xbox Wireless and PlayStation's dongle mode are generally faster than Bluetooth, adding 2 to 8ms. For competitive gaming, the difference between wired and Bluetooth is measurable and meaningful in precision-critical games. However, modern 2.4GHz wireless controllers are competitive with wired for most use cases.

Polling rate is how frequently a device reports its input state to the computer, measured in Hz. A 125Hz polling rate means the device reports every 8ms. A 1000Hz polling rate reports every 1ms. The polling interval creates the minimum possible input lag floor for that device — if the device polls at 125Hz, there is up to 8ms of delay before your last input is transmitted. Most standard controllers poll at 250Hz (4ms) to 1000Hz (1ms). Gaming mice often poll at 1000Hz or higher. Bluetooth devices are limited by the Bluetooth protocol's scheduling to around 125Hz effective polling regardless of the device's nominal rate.

Yes, especially in competitive and timing-based games. Input lag directly affects how quickly your character responds to your commands. In FPS games, high input lag means your aim adjustment arrives at the server later, giving opponents an effective reaction time advantage. In fighting games, frame-tight inputs require precision timing and high input lag makes one-frame links much harder. In rhythm games, input lag throws off timing accuracy. Professional esports players are highly sensitive to input lag and routinely test their peripherals and disable any system settings that add latency, including VSync and display image processing.

VSync prevents screen tearing by forcing the game to wait for the monitor's refresh cycle before sending a completed frame to the display. This creates a frame buffer that adds one full frame of render latency on top of your input lag. At 60fps, VSync adds up to 16.67ms. At 120fps it adds up to 8.33ms. This means a player running 60fps with VSync enabled experiences up to 16ms more input lag than one running the same frame rate without VSync. Using adaptive sync technologies like G-Sync or FreeSync instead eliminates screen tearing without the frame buffer delay that VSync introduces.

Yes, several software and settings changes reduce input lag without new hardware. Enabling Game Mode on your TV removes the image processing pipeline and can reduce display latency by 30 to 80ms. Disabling VSync or switching to G-Sync/FreeSync removes frame buffer delay. Setting Windows Power Plan to High Performance prevents CPU and USB throttling. Disabling USB selective suspend in Power Options eliminates wake-latency spikes. Updating controller firmware often improves polling stability. Closing background applications and browser tabs reduces CPU contention that causes scheduling jitter. Switching from a USB hub to a direct rear motherboard port removes hub polling overhead.

High jitter — a large difference between your minimum and maximum measured latency across rounds — is caused by inconsistent scheduling in the signal chain. Common causes include: background CPU processes competing with input polling, Bluetooth interference causing retransmissions, a USB hub sharing bandwidth between multiple devices, Windows USB selective suspend waking from a low-power state, or the browser's JavaScript event loop being delayed by other page activity. High jitter is often more disruptive than slightly higher but consistent latency, because the inconsistency makes your controls feel unpredictable. Switching to wired, using a rear USB port directly, and enabling High Performance mode typically reduce jitter significantly.

Reaction time is the biological delay between a human perceiving a stimulus and consciously initiating a motor response — typically 150 to 250ms for an average person. Input lag is the technical delay between the physical input action and the system registering it, typically 1 to 20ms for modern peripherals. This test measures both combined because they are impossible to separate in a browser environment. To isolate device latency, run many rounds and compare your average across different connection types (wired vs Bluetooth). The difference in average results between connection modes reflects the added device latency of the slower connection, since your human reaction time remains constant across both tests.

Yes, the input lag tester is completely free with no account, no registration, no email, and no usage limits. All latency calculations are performed locally in your browser using high-precision JavaScript timestamps. No test results, input data, or device information is ever transmitted to any server. You can run as many rounds as you like, test as many devices as needed, and compare wired versus wireless connections with no restrictions.