The CanvasRenderingContext2D.clearRect() method of the Canvas 2D API erases the pixels in a rectangular area by setting them to transparent black.

Note: Be aware that clearRect() may cause unintended side effects if you're not using paths properly. Make sure to call beginPath() before starting to draw new items after calling clearRect().


void ctx.clearRect(x, y, width, height);

The clearRect() method sets the pixels in a rectangular area to transparent black (rgba(0,0,0,0)). The rectangle's corner is at (x, y), and its size is specified by width and height.


The x-axis coordinate of the rectangle's starting point.
The y-axis coordinate of the rectangle's starting point.
The rectangle's width. Positive values are to the right, and negative to the left.
The rectangle's height. Positive values are down, and negative are up.


Erasing the whole canvas

This code snippet erases the entire canvas. This is commonly required at the start of each frame in an animation. The dimensions of the cleared area are set to equal the <canvas> element's width and height attributes.

const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');
ctx.clearRect(0, 0, canvas.width, canvas.height);

Erasing part of a canvas

This example draws a blue triangle on top of a yellowish background. The clearRect() method then erases part of the canvas.


<canvas id="canvas"></canvas>


The cleared area is rectangular in shape, with its top-left corner at (10, 10). The cleared area has a width of 120 and a height of 100.

const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');

// Draw yellow background
ctx.fillStyle = '#ff6';
ctx.fillRect(0, 0, canvas.width, canvas.height);

// Draw blue triangle
ctx.fillStyle = 'blue';
ctx.moveTo(20, 20);
ctx.lineTo(180, 20);
ctx.lineTo(130, 130);

// Clear part of the canvas
ctx.clearRect(10, 10, 120, 100);



Specification Status Comment
HTML Living Standard
The definition of 'CanvasRenderingContext2D.clearRect' in that specification.
Living Standard  

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
clearRectChrome Full support YesEdge Full support 12Firefox Full support 1.5IE Full support YesOpera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesFirefox Android Full support 4Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yes


Full support  
Full support

See also