Cubic-Bezier Easing Editor
Drag the two handles. The top graph is progress over time; the one beneath it is speed, which is what the eye actually sees.
Speed graph: height is how fast the element moves at that moment, relative to linear. Spikes are where it rushes, flat zero is where it stalls, below zero means it runs backwards.
CSS
Preview
1000ms
yours
ease
The boxes are animated by the browser with the real timing functions, not a simulation of them.