The animation-timing-function CSS property sets how an animation progresses through the duration of each cycle.

It is often convenient to use the shorthand property animation to set all animation properties at once.


/* Keyword values */
animation-timing-function: ease;
animation-timing-function: ease-in;
animation-timing-function: ease-out;
animation-timing-function: ease-in-out;
animation-timing-function: linear;
animation-timing-function: step-start;
animation-timing-function: step-end;

/* Function values */
animation-timing-function: cubic-bezier(0.1, 0.7, 1.0, 0.1);
animation-timing-function: steps(4, end);

/* Steps Function keywords */
animation-timing-function: steps(4, jump-start);
animation-timing-function: steps(10, jump-end);
animation-timing-function: steps(20, jump-none);
animation-timing-function: steps(5, jump-both);
animation-timing-function: steps(6, start);
animation-timing-function: steps(8, end);

/* Multiple animations */
animation-timing-function: ease, step-start, cubic-bezier(0.1, 0.7, 1.0, 0.1);

/* Global values */
animation-timing-function: inherit;
animation-timing-function: initial;
animation-timing-function: unset;

Timing functions may be specified on individual keyframes in a @keyframes rule. If no animation-timing-function is specified on a keyframe, the corresponding value of animation-timing-function from the element to which the animation is applied is used for that keyframe.

A keyframe's timing function is applied on a property-by-property basis from the keyframe on which it is specified until the next keyframe specifying that property, or until the end of the animation if there is no subsequent keyframe specifying that property. As a result, an animation-timing-function specified on the 100% or to keyframe will never be used.



The easing function that corresponds to a given animation, as determined by animation-name.

The non-step keyword values (ease, linear, ease-in-out, etc.) each represent cubic Bézier curve with fixed four point values, with the cubic-bezier() function value allowing for a non-predefined value. The step timing functions divides the input time into a specified number of intervals that are equal in length. It is defined by a number of steps and a step position.

Equal to cubic-bezier(0.25, 0.1, 0.25, 1.0), the default value, increases in velocity towards the middle of the animation, slowing back down at the end.
Equal to cubic-bezier(0.0, 0.0, 1.0, 1.0), animates at an even speed.
Equal to cubic-bezier(0.42, 0, 1.0, 1.0), starts off slowly, with the speed of the transition of the animating property increasing until complete.
Equal to cubic-bezier(0, 0, 0.58, 1.0), starts quickly, slowing down the animation continues. •
Equal to cubic-bezier(0.42, 0, 0.58, 1.0), with the animating properties slowly transitioning, speeding up, and then slowing down again.
cubic-bezier(p1, p2, p3, p4)
An author defined cubic-bezier curve, where the p1 and p3 values must be in the range of 0 to 1.
steps(n, <jumpterm>)
Displays an animation iteration along n stops along the transition, displaying each stop for equal lengths of time. For example, if n is 5, there are 5 steps. Whether the animation holds temporarily at 0%, 20%, 40%, 60% and 80%, on the 20%, 40%, 60%, 80% and 100%, or makes 5 stops between the 0% and 100% along the animation, or makes 5 stops including the 0% and 100% marks (on the 0%, 25%, 50%, 75%, and 100%) depends on which of the following jump terms is used:
Denotes a left-continuous function, so that the first jump happens when the animation begins;
Denotes a right-continuous function, so that the last jump happens when the animation ends;
There is no jump on either end. Instead, holding at both the 0% mark and the 100% mark, each for 1/n of the duration.
Includes pauses at both the 0% and 100% marks, effectively adding a step during the animation iteration.
Same as jump-start.
Same as jump-end.
Equal to steps(1, jump-start)
Equal to steps(1, jump-end)

Note: When you specify multiple comma-separated values on an animation-* property, they will be assigned to the animations specified in the animation-name property in different ways depending on how many there are. For more information, see Setting multiple animation property values.

Formal definition

Initial valueease
Applies toall elements, ::before and ::after pseudo-elements
Computed valueas specified
Animation typediscrete

Formal syntax

<easing-function>#where <easing-function> = linear | <cubic-bezier-timing-function> | <step-timing-function>where <cubic-bezier-timing-function> = ease | ease-in | ease-out | ease-in-out | cubic-bezier([0,1]>, <number>, [0,1]>, <number>)<step-timing-function> = step-start | step-end | steps(<integer>[, <step-position>]?)where <step-position> = jump-start | jump-end | jump-none | jump-both | start | end


Cubic-Bezier examples

.ease {
   animation-timing-function: ease;
.easein {
   animation-timing-function: ease-in;
.easeout {
   animation-timing-function: ease-out;
.easeinout {
   animation-timing-function: ease-in-out;
.linear {
   animation-timing-function: linear;
.cb {
   animation-timing-function: cubic-bezier(0.2,-2,0.8,2);

Step examples

.jump-start {
   animation-timing-function: steps(5, jump-start);
.jump-end {
   animation-timing-function: steps(5, jump-end);
.jump-none {
   animation-timing-function: steps(5, jump-none);
.jump-both {
   animation-timing-function: steps(5, jump-both);
.start {
   animation-timing-function: steps(5, start);
.end {
   animation-timing-function: steps(5, end);
.step-start {
   animation-timing-function: step-start;
.step-end {
   animation-timing-function: step-end;


Specification Status Comment
CSS Animations Level 1
The definition of 'animation-timing-function' in that specification.
Working Draft Initial definition.

Browser compatibility

BCD tables only load in the browser

See also