The transition-timing-function CSS property sets how intermediate values are calculated for CSS properties being affected by a transition effect.

This, in essence, lets you establish an acceleration curve so that the speed of the transition can vary over its duration.

This acceleration curve is defined using one <timing-function> for each property to be transitioned.

You may specify multiple timing functions; each one will be applied to the corresponding property as specified by the transition-property property, which acts as a master list. If there are fewer functions specified than in the master list, missing values are set to the initial value (ease). If there are more timing functions, the list is simply truncated to the right size. In both cases, the CSS declaration stays valid.

Syntax

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

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

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

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

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

Values

<timing-function>
Each <timing-function> represents the timing function to link to the corresponding property to transition, as defined in transition-property.

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.

ease
Equal to cubic-bezier(0.25, 0.1, 0.25, 1.0), the default value, increases in velocity towards the middle of the transition, slowing back down at the end.
linear
Equal to cubic-bezier(0.0, 0.0, 1.0, 1.0), transitions at an even speed.
ease-in
Equal to cubic-bezier(0.42, 0, 1.0, 1.0), starts off slowly, with the transition speed increasing until complete.
ease-out
Equal to cubic-bezier(0, 0, 0.58, 1.0), starts transitioning quickly, slowing down the transition continues. •
ease-in-out
Equal to cubic-bezier(0.42, 0, 0.58, 1.0), starts transitioning slowly, speeds up, and then slows 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 the transition along n stops along the transition, diplaying each stop for equal lengths of time. For example, if n is 5,  there are 5 steps. Whether the transition 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 transition, 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:
jump-start
Denotes a left-continuous function, so that the first jump happens when the transition begins;
jump-end
Denotes a right-continuous function, so that the last jump happens when the animation ends;
jump-none
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
jump-both
Includes pauses at both the 0% and 100% marks, effectively adding a step during the transition time.
start
Same as jump-start.
end
Same as jump-end.
step-start
Equal to steps(1, jump-start)
step-end
Equal to steps(1, jump-end)

Formal syntax

<single-transition-timing-function>#

where
<single-transition-timing-function> = <single-timing-function>

where
<single-timing-function> = linear | <cubic-bezier-timing-function> | <step-timing-function> | <frames-timing-function>

where
<cubic-bezier-timing-function> = ease | ease-in | ease-out | ease-in-out | cubic-bezier(<number>, <number>, <number>, <number>)
<step-timing-function> = step-start | step-end | steps(<integer>[, [ start | end ] ]?)
<frames-timing-function> = frames(<integer>)

Examples

Cubic-Bezier examples

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

Step examples

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

Accessibility concerns

Some animations can be helpful such as to guide users to understand what actions are expected, to show relationships within the user interface, and to inform users as to what actions have occurred. Animations can help reduce cognitive load, prevent change blindness, and establish better recall in spatial relationships. However, some animations can be problematic for people with cognitive concerns such as Attention Deficit Hyperactivity Disorder (ADHD) and certain kinds of motion can be a trigger for Vestibular disorders, epilepsy, and migraine and Scotopic sensitivity.

Consider providing a mechanism for pausing or disabling animation, as well as using the Reduced Motion Media Query to create a complimentary experience for users who have expressed a preference for no animated experiences.

Specifications

Specification Status Comment
CSS Transitions
The definition of 'transition-timing-function' in that specification.
Working Draft Initial definition

Initial valueease
Applies toall elements, ::before and ::after pseudo-elements
Inheritedno
Mediainteractive
Computed valueas specified
Animation typediscrete
Canonical orderthe unique non-ambiguous order defined by the formal grammar

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic supportChrome Full support 26
Full support 26
Full support Yes
Prefixed
Prefixed Implemented with the vendor prefix: -webkit-
Edge Full support 12
Full support 12
Full support 12
Prefixed
Prefixed Implemented with the vendor prefix: -webkit-
Firefox Full support 16
Full support 16
Full support 4
Prefixed
Prefixed Implemented with the vendor prefix: -moz-
Full support 49
Prefixed
Prefixed Implemented with the vendor prefix: -webkit-
Full support 44
Prefixed Disabled
Prefixed Implemented with the vendor prefix: -webkit-
Disabled From version 44: this feature is behind the layout.css.prefixes.webkit preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE Full support 10Opera Full support 12.1
Full support 12.1
Full support 15
Prefixed
Prefixed Implemented with the vendor prefix: -webkit-
No support 11.6 — 15
Prefixed
Prefixed Implemented with the vendor prefix: -o-
Safari Full support Yes
Full support Yes
Full support Yes
Prefixed
Prefixed Implemented with the vendor prefix: -webkit-
WebView Android Full support Yes
Full support Yes
Full support Yes
Prefixed
Prefixed Implemented with the vendor prefix: -webkit-
Chrome Android Full support 26
Full support 26
Full support Yes
Prefixed
Prefixed Implemented with the vendor prefix: -webkit-
Edge Mobile Full support 12
Full support 12
Full support 12
Prefixed
Prefixed Implemented with the vendor prefix: -webkit-
Firefox Android Full support 16
Full support 16
Full support 4
Prefixed
Prefixed Implemented with the vendor prefix: -moz-
Full support 49
Prefixed
Prefixed Implemented with the vendor prefix: -webkit-
Full support 44
Prefixed Disabled
Prefixed Implemented with the vendor prefix: -webkit-
Disabled From version 44: this feature is behind the layout.css.prefixes.webkit preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android ? Safari iOS Full support Yes
Full support Yes
Full support Yes
Prefixed
Prefixed Implemented with the vendor prefix: -webkit-
Samsung Internet Android Full support Yes
Full support Yes
Full support Yes
Prefixed
Prefixed Implemented with the vendor prefix: -webkit-
jump- keywords for steps()
Experimental
Chrome ? Edge ? Firefox Full support 65IE ? Opera ? Safari ? WebView Android ? Chrome Android ? Edge Mobile ? Firefox Android Full support 65Opera Android ? Safari iOS ? Samsung Internet Android ?

Legend

Full support  
Full support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
User must explicitly enable this feature.
User must explicitly enable this feature.
Requires a vendor prefix or different name for use.
Requires a vendor prefix or different name for use.

See also

Document Tags and Contributors

Last updated by: estelle,