Response Time vs Input Lag: What's the Difference?
The complete guide to understanding these commonly confused monitor specs
Quick Navigation
The Quick Answer
Response Time
How fast pixels change color
- Affects: Motion blur & ghosting
- Measured in: ms (GtG or MPRT)
- Good: Under 5ms GtG
Input Lag
Delay from action to screen update
- Affects: Control responsiveness
- Measured in: ms (total system lag)
- Good: Under 10ms for gaming
Think of it this way: Response time affects what you see (visual quality). Input lag affects what you feel (control responsiveness). Both matter, but for different reasons.
What is Response Time?
Response time measures how quickly a pixel can change from one color to another. When pixels are slow to change, you see ghosting - a trail or shadow behind moving objects.
Types of Response Time Measurements
GtG (Gray-to-Gray)
Time for pixels to transition between gray shades. Most useful real-world measurement. Look for under 5ms GtG for gaming.
MPRT (Moving Picture Response Time)
Measures perceived blur, not actual pixel speed. Can be artificially improved with backlight strobing. Often used for misleading "1ms" marketing claims.
BtW (Black-to-White)
Older measurement rarely used now. Measures easiest transition, not representative of real performance.
What Slow Response Time Looks Like
- - Ghosting: Shadow trails behind moving objects (characters, text, UI elements)
- - Smearing: Dark colors take longer to transition, especially on VA panels
- - Overshoot: When overdrive is set too high, pixels overshoot and create inverse ghosting
Response Time by Panel Type
| Panel Type | Typical GtG | Notes |
|---|---|---|
| OLED | 0.03-0.1ms | Instant response, no ghosting |
| TN | 1-2ms | Fast but poor colors/viewing angles |
| Fast IPS | 2-4ms | Best balance for most gamers |
| VA | 4-8ms | Slower dark transitions, smearing possible |
What is Input Lag?
Input lag is the total delay between your action (pressing a button, moving your mouse) and the result appearing on screen. This includes processing by your PC, the monitor's internal processing, and display output.
Components of Total Input Lag
Total system input lag typically ranges from 20-80ms depending on hardware and settings.
What High Input Lag Feels Like
- - Delayed response: Controls feel sluggish or unresponsive
- - Missed shots: Enemies move past your crosshair before your shot registers
- - Floaty controls: Movement and aiming feel disconnected from your inputs
Input Lag Benchmarks
| Input Lag | Rating | Experience |
|---|---|---|
| <5ms | Excellent | Instant, professional esports level |
| 5-10ms | Great | Imperceptible for most gamers |
| 10-20ms | Good | Fine for casual gaming |
| 20-50ms | Noticeable | Detectable, affects competitive play |
| >50ms | Poor | Clearly laggy, frustrating |
Side-by-Side Comparison
| Aspect | Response Time | Input Lag |
|---|---|---|
| What it measures | Pixel color transition speed | Input-to-display delay |
| Primary effect | Motion clarity, ghosting | Control responsiveness |
| Typical range | 0.03ms - 10ms | 2ms - 100ms+ |
| Target for gaming | <5ms GtG | <10ms |
| Listed on spec sheets? | Yes (often misleading) | Rarely |
| You can test yourself? | Visually only | Yes, with tools |
| Affected by | Panel type, overdrive | Monitor processing, refresh rate |
Which Matters More for Gaming?
The short answer: both matter, but for different types of gamers.
Prioritize Input Lag If You:
- + Play competitive FPS (Valorant, CS2, Apex)
- + Need every millisecond advantage
- + Play fighting games (frame-perfect inputs)
- + Play rhythm games (timing critical)
- + Are switching from a high-end monitor
Prioritize Response Time If You:
- + Are sensitive to ghosting/motion blur
- + Play fast-paced games with lots of motion
- + Use high refresh rates (144Hz+)
- + Watch fast action movies/sports
- + Use dark themes and notice smearing
The Good News
Most modern gaming monitors excel at both. Any 144Hz+ gaming monitor from a reputable brand will have under 10ms input lag and under 5ms response time. Focus on panel type, refresh rate, and resolution first - input lag and response time will follow.
Decoding Marketing Claims
Monitor manufacturers love to play games with response time specs. Here's how to see through the marketing.
"1ms Response Time"
Almost always MPRT, not GtG. MPRT is measured with backlight strobing enabled, which reduces brightness and causes flicker sensitivity for some users. Real GtG is usually 3-5ms on these panels.
What to check: Look for independent reviews with actual GtG measurements.
"0.5ms Response Time"
Only possible with OLED or measured under unrealistic conditions. If you see this on an IPS/VA monitor, it's marketing nonsense.
What to check: Is it OLED? If not, be skeptical.
"Low Input Lag" (No Number)
If they don't give a number, they're hiding something. Reputable gaming monitors list input lag or it's measurable in independent reviews.
What to check: Look for reviews from rtings.com, Hardware Unboxed, or TFTCentral.
"Gaming Mode" on TVs
This actually matters. Game Mode disables post-processing that can add 50-100ms of input lag. Always enable it for gaming on TVs.
What to check: Verify the TV has a true Game Mode that reduces input lag to under 20ms.
How to Test Your Monitor
Testing Response Time
You can't measure exact response time without equipment, but you can test for ghosting:
- 1. Use our Refresh Rate Test UFO animation
- 2. Look for trails behind moving objects
- 3. Test with different overdrive settings
- 4. Dark backgrounds show smearing more clearly
Testing Input Lag
Use our interactive input lag test tool:
- 1. Go to our Input Lag Test
- 2. Click when the moving target reaches the line
- 3. Compare results between monitors
- 4. Test in different picture modes
Frequently Asked Questions
What is the difference between response time and input lag?
Response time measures how fast pixels change color (affects motion clarity). Input lag measures the delay between your action and the screen showing it (affects control feel). They are completely different metrics that happen to both be measured in milliseconds.
Is 1ms response time actually better than 4ms?
Not necessarily. Marketing "1ms" claims (usually MPRT) aren't comparable to real-world GtG measurements. A quality 4ms GtG IPS panel often performs better than a budget "1ms" panel. Look for independent reviews with actual measurements.
What is a good input lag for gaming?
For competitive gaming, aim for under 10ms total input lag. Most gaming monitors achieve 4-8ms. Casual gamers may not notice up to 20ms. If using a TV, enable Game Mode to reduce input lag from 50-100ms down to 10-20ms.
Does refresh rate affect input lag?
Yes. Higher refresh rates reduce input lag because frames are delivered more frequently. At 60Hz, each frame takes 16.67ms; at 144Hz, it's 6.94ms; at 240Hz, just 4.17ms. This is why 144Hz+ monitors feel more responsive.
Which matters more: response time or input lag?
Input lag matters more for competitive gaming (reaction advantage). Response time matters more for visual quality (ghosting/blur). For the best experience, prioritize both: under 10ms input lag and under 5ms GtG response time.