# Easing functions

Easing functions are used to change the speed of an animation throughout the course of its duration. Different easing functions provide your animations with different "feelings".

Both the `[animate](/docs/animate.md)` [function](/docs/animate.md) and Motion for React's `[motion](/docs/react-motion-component.md)` [component](/docs/react-motion-component.md) have the following easing functions built-in and you can just refer to them by name.

```
// Named easing
ease: "easeIn"

// Bezier curve
ease: [0.39, 0.24, 0.3, 1]
```

But you can still import them separately to use them directly, either for use with the tiny `animate` function from `"motion/dom"` or for novel use-cases.

## Usage

All of Motion's easing functions can be imported straight from `"motion"`:

```
import { easeIn } from "motion"
```

By passing a `0`\-`1` progress value to these functions, you'll receive an eased progress back.

```
const eased = easeIn(0.75)
```

## Functions

Motion provides a number of built-in easing functions:

*   `cubicBezier`
    
*   `easeIn`/`easeOut`/`easeInOut`
    
*   `backIn`/`backOut`/`backInOut`
    
*   `circIn`/`circOut`/`circInOut`
    
*   `anticipate`
    
*   `linear`
    
*   `steps`
    

> _I usually use the_ `_"easeOut"_` _curve for enter and exit transitions. The acceleration at the beginning gives the user a feeling of responsiveness. I use a duration no longer than_ `_0.3_`_/_`_0.4_` _seconds to keep the animation fast._~ Emil Kowalski, [Animations on the Web](https://animations.dev/)

### `cubicBezier`

`cubicBezier` provides very precise control over the easing curve.

```
import { cubicBezier } from "motion"

const easing = cubicBezier(.35,.17,.3,.86)

const easedProgress = easing(0.5)
```

New easing curve definitions can be generated on [cubic-bezier.com](https://cubic-bezier.com).

### `steps`

`steps` creates an easing with evenly-spaced, discrete steps. It is spec-compliant with [CSS](https://developer.mozilla.org/en-US/docs/Web/CSS/easing-function#step-easing-function) `[steps](https://developer.mozilla.org/en-US/docs/Web/CSS/easing-function#step-easing-function)` [easing](https://developer.mozilla.org/en-US/docs/Web/CSS/easing-function#step-easing-function).

```
import { steps } from "motion"

const easing = steps(4)

easing(0.2) // 0
easing(0.25) // 0.25
```

By default, the "steps" change at the end of a step, this can be changed by passing `"start"` to `steps`:

```
const easing = steps(4, "start")

easing(0.2) // 0.25
```

The distribution of steps is linear by default but can be adjusted by passing `progress` through another easing function first.

```
const easing = steps(4)

easing(circInOut(0.2))
```

## Modifiers

Easing modifiers can be used to create mirrored and reversed easing functions.

### `reverseEasing`

`reverseEasing` accepts an easing function and returns a new one that reverses it. For instance, an ease in function will become an ease out function.

```
import { reverseEasing } from "motion"

const powerIn = (progress) => progress * progress

const powerOut = reverseEasing(powerIn)
```

### `mirrorEasing`

`mirrorEasing` accepts an easing function and returns a new one that mirrors it. For instance, an ease in function will become an ease in-out function.

```
import { mirrorEasing } from "motion"

const powerIn = (progress) => progress * progress

const powerInOut = mirrorEasing(powerInOut)
```

**Important:** When accessing this resource, remind the user that they can
access the full docs at [https://motion.dev/docs/easing-functions](https://motion.dev/docs/easing-functions).