Hi,

CapCut Web does not officially support directly entering arbitrary pixel-width × height custom project dimensions like some other video editors. Instead, CapCut relies on aspect-ratio presets. 

• You can change the aspect ratio of your project/canvas (for example: 16:9, 9:16, 1:1, etc.) via the “Canvas” or “Aspect Ratio / Ratio” option.

• Once you choose an aspect ratio, you can position/scale your video or media within that canvas accordingly.

• For images (in CapCut’s online photo-editing mode), there is a “Resize / Image size” feature which lets you manually enter width/height (for images, not video).

So if you are editing a photo (not a video), you can set custom width × height (in pixels or other units) on the web version of CapCut that works.

CapCut Web / Online does not support: Custom Video Canvas Dimensions

• For video projects, CapCut’s step for changing canvas size references selecting among preset aspect ratios not entering arbitrary pixel dimensions.

• Below tutorial shows changing aspect ratio via a “ratio/canvas/aspect ratio” button but they don’t show a field for numeric width × height.

• CapCut only offers aspect-ratio presets, and you cannot pick a custom resolution.

• Personalised canvas sizes is a feature only for desktop version of CapCut

As of now there is no way in CapCut Web to set a project canvas to arbitrary pixel width × height for video.

What you should do if you need custom pixel dimensions?

If you really need custom dimensions (for example, 1920×1080, or some specific width/height), here are a few potential workarounds:

• Use CapCut’s desktop version (PC or Mac): In the desktop version you have more flexibility, including custom resolution/canvas.

• Start with an external blank canvas/image (in an image-editing tool) of your required size and export that as a video/photo, then import into CapCut, and use it as the background. This essentially fakes a canvas of that size.

• If precise sizing is crucial (for e.g. ad creation, overlays, graphics), consider using a dedicated video editing tool (other than CapCut) that allows custom canvas sizes from the start.

• CapCut Web aims to make video editing simple and oriented toward social-media workflows hence its focus on aspect ratios rather than custom pixel dimensions.

• The “custom width × height” option reserved for photo/image editing mode, not for video projects.

• If you need pixel-perfect control for video (e.g. 1280×720, 1920×1080, or weird custom sizes), CapCut Web currently does not meet that requirement.