FPS to ms Converter
FPS to milliseconds and back, with the frame budget spelled out.
Think in milliseconds, not FPS
Frame time = 1000 / fps: 60 fps is 16.67 ms, 144 fps is 6.94 ms, 30 fps is 33.3 ms. FPS is misleading for optimization because it's nonlinear: going from 300 to 250 fps loses 0.67 ms, while 60 to 55 fps loses 1.5 ms. A '5 fps drop' means nothing without knowing where you started; a millisecond is a millisecond.
Budgeting a frame
At 60 fps everything (input, simulation, rendering, and whatever the driver takes) must fit in 16.67 ms. A 2 ms shadow pass is 12% of that budget but 29% of a 144 fps budget: the same feature gets more expensive the faster you want to run.