Frame rate and frame time
Frame time is the time each frame is on screen: 1,000 divided by the frame rate. At 60 frames per second that is 16.67 milliseconds, and at 144 it is 6.94.
Frame time is the more useful figure when you are chasing stutter, because a smooth 60 has consistent 16.67 ms frames while an average of 60 built from 8 ms and 40 ms frames feels worse.
Worked example
Running at 60 frames per second on a 144 Hz display gives a frame time of 16.67 ms against a refresh interval of 6.94 ms. The display produces 0.42 frames per refresh, so it repeats each frame about two and a half times.
At 60 fps on a 60 Hz display the two figures match and each refresh carries one new frame.
Why the refresh rate caps what you see
A display can only show a new image on each refresh. Frames produced faster than the refresh rate are discarded, so 200 fps on a 60 Hz panel looks like 60 fps with tearing.
Variable refresh rate changes the timing rather than the number of frames, which removes tearing but does not make a slow frame appear faster.
Limits of this calculator
It converts averages. It does not model frame pacing, 1 per cent low figures, latency or the effect of a frame cap.
It does not know whether your graphics card can reach the frame rate you entered; that is a benchmark question, not arithmetic.
To see which component limits the frame rate, use the bottleneck calculator.
Inputs for the FPS calculator
Frame rate
Frames per second you measured or expect, as an average rather than a peak.
Monitor refresh rate
The refresh rate the display is actually running at, not its maximum specification.
CALCULATOR QUESTIONS
FPS calculator questions
Is a higher frame rate always smoother?
Only up to the refresh rate. Beyond it, extra frames are discarded unless the display supports a higher rate.
What is frame time?
The duration each frame is displayed, 1,000 divided by the frame rate in milliseconds.
Why does 60 fps feel worse on some systems?
Frame pacing. An average of 60 with uneven frame times feels rougher than a steady 60.
Does this account for G-Sync or FreeSync?
No. Variable refresh changes the timing, which this arithmetic does not model.