transition-duration

Specifies how long an elements transition should take to complete.

transition-duration: <value>;

The transition-duration value can be specified by one of the folllowing:

• Seconds: 2s
• Milliseconds: 125ms

Note: We can give a comma-separated list of values to set different durations for properties of the same element. The duration of all properties will be the same if a single value is provided.

Setting a h1 element to complete its transition over a duration of 3 seconds.

h1 {
  transition-duration: 3s;
}

Setting a div elements height transition to last 4 seconds and color transiton to last 200 milliseconds.

div {
  transition-duration: 4s, 200ms;
  transition-property: height, color;
}