Input Lag Calculator

About Input Lag Calculator

Input lag is the total time between pressing a button and seeing the result on screen. This calculator breaks that delay into its individual components - display refresh, pixel response, USB polling, frame rendering, and V-Sync overhead - so you can see exactly where your latency comes from and which upgrades would make the biggest difference.

How Total Input Lag Is Calculated

The signal chain from a mouse click to a screen update passes through several stages, each adding latency. This calculator uses average-case values for each component and sums them to produce a total estimate.

Component	Formula	What It Represents
Display latency	(1000 / refresh rate) / 2	On average, you are halfway through a display refresh cycle when input happens
Pixel response time	Full GtG response time	Time for a pixel to change from one colour to another (grey-to-grey)
USB polling delay	(1000 / polling rate) / 2	On average, your input arrives halfway between two polling intervals
Frame render time	(1000 / FPS) / 2	On average, input arrives halfway through a frame being rendered
V-Sync penalty	1000 / refresh rate (if enabled)	V-Sync holds the frame until the next refresh, adding up to one full frame of delay

The total is the sum of all five components. This gives a reasonable middle-ground estimate. The actual worst case would be higher (all components at maximum), and the best case lower (all at minimum).

Worked Example: 144 Hz Gaming Setup

Take a typical gaming setup: 144 Hz monitor, 4 ms GtG response, 1000 Hz mouse, rendering at 200 FPS, V-Sync off.

Component	Calculation	Latency
Display latency	(1000 / 144) / 2	3.47 ms
Pixel response	4 ms GtG	4.00 ms
USB polling	(1000 / 1000) / 2	0.50 ms
Frame render	(1000 / 200) / 2	2.50 ms
V-Sync penalty	Off	0.00 ms
Total		10.47 ms

Now compare that to a 60 Hz office monitor with V-Sync on and a 125 Hz mouse: the total jumps to around 42 ms. That 30+ ms difference is absolutely noticeable in fast-paced games. For more on frame timing, see the FPS calculator.

Preset Comparisons

The calculator includes four built-in presets covering common setups. Use the Compare button to see all four side by side.

Preset	Refresh Rate	Response Time	Polling Rate	FPS	V-Sync	Approx. Total
Competitive eSports	360 Hz	1 ms	1000 Hz	500+	Off	~4 ms
Standard Gaming	144 Hz	4 ms	1000 Hz	144	Off	~11 ms
Console Gaming	60 Hz	8 ms	125 Hz	60	On	~42 ms
Casual / Office	60 Hz	12 ms	125 Hz	60	On	~46 ms

Which Component Matters Most?

Not all latency sources are equally impactful. Here is a rough ranking of what makes the biggest difference when upgrading, based on how much latency each change typically removes:

Upgrade	Typical Latency Reduction	Cost	Impact Rating
60 Hz to 144 Hz monitor	~7 ms from display + enables higher FPS ceiling	Medium	Very high
Disable V-Sync (or use adaptive sync)	8-16 ms (one full frame at 60-120 Hz)	Free	Very high
Increase FPS (lower settings or faster GPU)	3-8 ms depending on starting FPS	Free to high	High
125 Hz to 1000 Hz mouse polling	~3.5 ms	Low	Moderate
144 Hz to 360 Hz monitor	~2 ms from display	High	Moderate
4 ms to 1 ms response time	3 ms	Medium	Low to moderate
1000 Hz to 4000 Hz mouse polling	~0.4 ms	Medium	Very low

The two cheapest and most impactful changes are disabling V-Sync (free) and upgrading from a 60 Hz to a 144 Hz monitor. Going beyond 1000 Hz mouse polling or 1 ms response time gives diminishing returns that only matter at the highest competitive levels.

V-Sync, G-Sync, and FreeSync Explained

V-Sync synchronises GPU frame output with monitor refresh to prevent screen tearing. The tradeoff is added latency - the GPU must wait for the monitor's refresh cycle, adding up to one full frame of delay. Adaptive sync technologies avoid this tradeoff.

Technology	How It Works	Tearing	Added Latency	Requirements
V-Sync	GPU waits for monitor refresh to push frame	None	Up to 1 frame (16.7 ms at 60 Hz)	Any monitor
G-Sync (NVIDIA)	Monitor adjusts refresh rate to match GPU output	None	Near zero	G-Sync compatible monitor + NVIDIA GPU
FreeSync (AMD)	Monitor adjusts refresh rate to match GPU output	None	Near zero	FreeSync monitor + AMD or NVIDIA GPU
V-Sync off	GPU pushes frames immediately	Possible	None	Any monitor
NVIDIA Reflex	Reduces render queue to minimise GPU-side latency	Depends on V-Sync setting	Reduces by 5-20 ms	Supported game + NVIDIA GPU

If your monitor supports G-Sync or FreeSync, enable it and turn V-Sync off in the game. You get tear-free gameplay with minimal added latency.

USB Polling Rate: Does 4000 Hz or 8000 Hz Matter?

At 125 Hz polling, the mouse reports its position every 8 ms. At 1000 Hz, it reports every 1 ms. Some newer mice go to 4000 Hz (0.25 ms) or even 8000 Hz (0.125 ms). In practice, 1000 Hz is the sweet spot. The jump from 125 Hz to 1000 Hz saves about 3.5 ms of average polling latency. The jump from 1000 Hz to 8000 Hz saves only 0.44 ms. Very few people can perceive that difference, and high polling rates increase CPU usage slightly.

Polling Rate	Report Interval	Average Polling Latency	Saving vs Previous Tier
125 Hz	8.00 ms	4.00 ms	-
500 Hz	2.00 ms	1.00 ms	3.00 ms
1000 Hz	1.00 ms	0.50 ms	0.50 ms
4000 Hz	0.25 ms	0.125 ms	0.375 ms
8000 Hz	0.125 ms	0.0625 ms	0.0625 ms

Monitor Response Time: GtG vs MPRT

Monitor manufacturers quote two different response time specs, and they measure different things:

Spec	What It Measures	Typical Values	What It Affects
GtG (Grey to Grey)	Time for a pixel to transition between two grey levels	1-8 ms on modern panels	Ghosting and smearing behind moving objects
MPRT (Moving Picture Response Time)	How long a pixel is visible per frame, accounting for sample-and-hold blur	1-4 ms with backlight strobing	Perceived motion clarity and sharpness

GtG is the more relevant number for input lag calculations because it directly measures how long the pixel transition takes. MPRT is about motion clarity, which is related but separate. Manufacturers sometimes advertise MPRT numbers because they look lower, so check which spec you are reading.

To work out the right screen size and pixel density for your desk, the monitor size calculator covers all common aspect ratios and resolutions. All calculations run in your browser with no data sent anywhere.