Suggest an editImprove this articleRefine the answer for “What does the transition-timing-function property do?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**`transition-timing-function`** is a CSS property that defines the pacing curve of a smooth transition: uniform, slowing down, or speeding up. **Key point:** the property defines exactly how the animation's speed changes during the transition.Shown above the full answer for quick recall.Answer (EN)Image`transition-timing-function` defines **the pacing curve** along which the smooth transition happens: whether it is uniform, slows down, speeds up, and so on. Main values: ```javascript ease - smooth acceleration and deceleration (the default value) linear - uniform speed from start to end ease-in - slow at the start, faster toward the end ease-out - fast at the start, slower toward the end ease-in-out - slow at the start and end, faster in the middle ``` Cubic Bezier curves can also be used: ```javascript transition-timing-function: cubic-bezier(.25, .1, .25, 1); ``` **Summary:** the property defines *exactly how* the animation's speed changes during the transition: uniformly or with acceleration/deceleration.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.