Monitor Response Time Calculator
Check whether a monitor's response time fits within one refresh at your refresh rate, and estimate the motion blur caused by each frame staying on screen. Works with spec-sheet or measured figures for TN, IPS, VA and OLED.
What This Calculator Tells You
Response time (GtG, grey-to-grey) is how long a pixel takes to change from one shade to another. This calculator compares a monitor's response time with the length of one refresh at its refresh rate, so you can see whether pixel transitions finish before the next frame arrives. It also estimates the motion blur that comes from how long each frame stays on screen, which matters as much as response time and which a response-time figure alone doesn't show.
It doesn't know how a particular monitor performs. Real response times vary between models, settings and even individual transitions, and can only be measured. For a realistic result, enter a measured average from an independent review rather than the number on the box.
How to Use It
- Enter the response time. Ideally a measured average from a review site that tests monitors (such as RTINGS, Monitors Unboxed or TFT Central); otherwise the manufacturer's "GtG" figure.
- Say where it came from, so the results can tell you how much to trust it.
- Enter the refresh rate you run the monitor at and, if your games run slower than that, the actual frame rate.
- Pick the panel type and, optionally, the overdrive setting for advice specific to them.
Response Time and Refresh Rate
Each refresh lasts 1000 ÷ refresh rate milliseconds. If a pixel transition takes longer than that, it's still under way when the next frame starts, and moving objects leave a visible trail. A common rule of thumb is that the average response time should fit comfortably inside one refresh.
| Refresh rate | Time per refresh | Persistence blur at 1000 px/s |
|---|---|---|
| 60 Hz | 16.67 ms | ≈ 17 px |
| 120 Hz | 8.33 ms | ≈ 8 px |
| 144 Hz | 6.94 ms | ≈ 7 px |
| 165 Hz | 6.06 ms | ≈ 6 px |
| 240 Hz | 4.17 ms | ≈ 4 px |
| 360 Hz | 2.78 ms | ≈ 3 px |
| 480 Hz | 2.08 ms | ≈ 2 px |
The blur column assumes the game runs at the full refresh rate and the monitor isn't strobing its backlight.
Why Fast Pixels Still Blur: Persistence
Most monitors are sample-and-hold: each frame stays lit for the whole refresh. When your eyes follow a moving object, the image is frozen while your eyes keep moving, so its edges smear. As a rule of thumb from Blur Busters, each millisecond a frame is held adds about one pixel of blur for motion at 1000 pixels per second.
That's why even an OLED with near-instant pixels shows around 17 px of blur at 60 Hz, and why going from 60 to 240 Hz (and frame rate) cuts blur to about a quarter. Backlight strobing and black frame insertion shorten how long each frame is shown, which reduces blur further, usually at the cost of brightness.
This is also what MPRT (moving picture response time) measures. A "1ms MPRT" specification usually depends on a strobing mode, and on many monitors that mode can't be used together with variable refresh rate (G-Sync/FreeSync). MPRT and GtG measure different things, so don't compare one with the other.
Overdrive
Overdrive (also called Response Time, Trace Free or AMA in monitor menus) briefly drives LCD pixels harder to speed up transitions. Too much of it makes pixels overshoot their target, which shows as bright or coloured halos behind moving objects, called overshoot or inverse ghosting.
- Spec-sheet response times are typically measured at the strongest overdrive setting.
- The strongest setting is often not the best one; many monitors look cleanest one step lower.
- Some monitors tune overdrive for their maximum refresh rate only, so the same setting can overshoot at 60 Hz.
- Compare settings yourself with the TestUFO ghosting test.
- OLED panels don't need or offer overdrive.
Worked Examples
IPS monitor, 4 ms measured, 144 Hz
One refresh lasts 6.94 ms, so the transition takes 58% of it: it finishes in time, but without much margin. Persistence blur is about 7 px at 1000 px/s.
VA monitor, 8 ms measured, 240 Hz
One refresh lasts 4.17 ms, so transitions run well past it and moving objects will trail, especially in dark scenes where VA transitions are often slowest.
OLED monitor, 0.1 ms, 60 Hz
Pixel response is no problem at all, yet persistence blur is still about 17 px because each frame is held for 16.67 ms. A higher refresh and frame rate would make far more difference than faster pixels.
Limitations
- The result is only as good as the response time you enter. An average can hide individual transitions that are much slower.
- The panel notes are general; individual models within each panel type differ widely.
- Backlight strobing, black frame insertion, input lag and overshoot aren't calculated.
- Perceived blur also depends on how fast things move on screen and on your eyes tracking them; 1000 px/s is a common reference speed.
The numbers you enter are sent to Orbit2x's server to calculate the result and aren't saved. See the privacy policy.
Frequently Asked Questions
Is a 1 ms response time necessary for gaming?
Not in itself. What matters is that real transitions fit within your refresh, and at 144 Hz that's 6.94 ms. Beyond that, motion clarity is limited more by persistence, which depends on refresh and frame rate, than by the last millisecond of response time.
Why does my "1ms" monitor still smear?
The figure is usually the fastest transition at the strongest overdrive setting. Other transitions, especially dark ones on VA panels, can be much slower. And even with instant pixels, sample-and-hold persistence still blurs motion.
What's the difference between GtG and MPRT?
GtG measures how fast pixels change colour. MPRT measures how long each frame is visible, which is what causes persistence blur. A low MPRT figure usually needs backlight strobing.
Does a higher refresh rate help a slow panel?
It reduces persistence blur, but each refresh is shorter, so a slow panel's transitions take a larger share of it and can look more smeared. That's why a fast refresh rate needs a correspondingly fast panel.