---
title: "onSizeChanged"
description: "Invoked with the size of the modified Compose UI element when the element is first measured or
when the size of the element changes.

There are no guarantees `onSizeChanged` will not be re-invoked with the same size.

Using the `onSizeChanged` size value in a [MutableState] to update layout causes the new size
value to be read and the layout to be recomposed in the succeeding frame, resulting in a one
frame lag.

You can use `onSizeChanged` to affect drawing operations. Use [Layout] or [SubcomposeLayout] to
enable the size of one component to affect the size of another."
type: "modifier"
---

<div class='type'>Compose Modifier</div>

<a id='references'></a>
<div class='sourceset sourceset-common'>Common</div>


```kotlin
fun Modifier.onSizeChanged(onSizeChanged: (IntSize) -> Unit) =
    this.then(OnSizeChangedModifier(onSizeChanged = onSizeChanged))
```


Invoked with the size of the modified Compose UI element when the element is first measured or
when the size of the element changes.

There are no guarantees `onSizeChanged` will not be re-invoked with the same size.

Using the `onSizeChanged` size value in a `MutableState` to update layout causes the new size
value to be read and the layout to be recomposed in the succeeding frame, resulting in a one
frame lag.

You can use `onSizeChanged` to affect drawing operations. Use `Layout` or `SubcomposeLayout` to
enable the size of one component to affect the size of another.



## Code Examples
### OnSizeChangedSample
```kotlin
@Composable
fun OnSizeChangedSample(name: String) {
    // Use onSizeChanged() for diagnostics. Use Layout or SubcomposeLayout if you want
    // to use the size of one component to affect the size of another component.
    Text(
        "Hello $name",
        Modifier.onSizeChanged { size -> println("The size of the Text in pixels is $size") },
    )
}
```