How to Crop Your Webcam in OBS Studio

The short answer

In OBS Studio you can crop a webcam without changing anything on the camera itself. There are three built-in ways. The quickest is to hold Alt (Option on a Mac) and drag an edge of the webcam source in the preview. For exact pixel values, open Edit Transform. If you want the same crop wherever that webcam appears, use a Crop/Pad filter. All three trim the edges of the image inside OBS. None of them changes the resolution the camera actually sends.

One distinction changes which method you need. Cropping removes part of the picture, such as a cluttered edge of the room. Resizing or scaling makes the whole picture bigger or smaller on the canvas, and the canvas is OBS's output frame. Dragging the corner handles without Alt only resizes. If you want a round or other non-rectangular webcam, a straight crop won't do it, and you need the mask method described near the end.

Before you start

• OBS Studio is installed and your webcam has been added as a Video Capture Device source in a scene.
• The webcam image is visible in the OBS preview. If it is black, solve that first. Common causes are another app holding the camera or the operating system blocking camera access for OBS. Cropping can't fix either.
• You know which edges you want to remove. No specific crop values are recommended here because they depend entirely on your framing.

Menu names and layouts can vary slightly between OBS versions and operating systems. The steps below describe the general OBS Studio interface. They have not been verified against a specific release.

Method 1: Alt-drag in the preview (fastest)

• 1. Click the webcam source in the Sources list or in the preview so a red bounding box with handles appears around it.
• 2. Hold Alt (Windows and Linux) or Option (macOS).
• 3. Drag the handle on the edge you want to trim inward. The image is cut off instead of shrinking.
• 4. Release the mouse, then release the key.
• 5. Repeat for any other edges.

How to know it worked: the picture should lose its edges instead of getting smaller, and the cropped side of the bounding box changes color to show a crop is applied. If the whole image shrank instead, the modifier key wasn't held. Press Ctrl+Z (Cmd+Z on Mac) or reset the transform and try again.

On some Linux desktops, Alt-drag is reserved for moving windows, so OBS never receives it. If that happens, use Method 2.

Method 2: Edit Transform (exact pixel values)

• 1. Right-click the webcam source and choose Transform, then Edit Transform. The keyboard shortcut is usually Ctrl+E, or Cmd+E on Mac.
• 2. Find the Crop fields for Left, Right, Top and Bottom.
• 3. Enter the number of pixels to remove from each side. The changes show in the preview right away.
• 4. Close the window.

How to know it worked: the preview shows the trimmed image, and reopening Edit Transform shows the values you entered. This method suits matching crops across several scenes or making small, repeatable adjustments.

Methods 1 and 2 apply only to that copy of the webcam in that scene. If you add the same webcam to another scene, it appears uncropped there.

Method 3: Crop/Pad filter (same crop everywhere)

• 1. Right-click the webcam source and choose Filters.
• 2. Under Effect Filters, click the plus button and choose Crop/Pad.
• 3. Name the filter and confirm.
• 4. Enter values for Left, Top, Right and Bottom. If you clear the Relative option, you can instead set a starting position (X and Y) and a fixed width and height.
• 5. Close the Filters window.

How to know it worked: the filter's own preview shows the cropped image, and the webcam looks the same in every scene that uses this source. To compare against the original, toggle the eye icon next to the filter. This turns the crop off without deleting it.

After cropping: fill the frame and keep it sharp

A cropped webcam leaves empty space on the canvas. You can drag the corner handles without Alt to enlarge it, or right-click the source and use Transform options such as Fit to Screen. Enlarging a cropped image stretches fewer camera pixels over a larger area, so heavy crops can look softer. If your camera supports a higher resolution, select it in the Video Capture Device properties before cropping. That leaves more detail to work with.

To undo all of this, right-click the source and choose Transform, then Reset Transform. This clears transform crops and scaling. A Crop/Pad filter has to be removed or disabled separately in the Filters window.

Using the cropped webcam in a video call

Your crop only reaches a call if the call app receives video from OBS. Selecting the physical webcam in the call app bypasses OBS entirely. To send the cropped image, click Start Virtual Camera in OBS and choose the OBS virtual camera as the camera in the call app.

By default the virtual camera sends OBS's main output, meaning the whole canvas. Any empty area left around a cropped webcam will appear in the call. To avoid this, scale the webcam to fill the canvas. Some OBS versions also let you choose a specific scene or source as the virtual camera output, using the settings next to the Start Virtual Camera button.

Check the result in stages, because each stage confirms something different:

• OBS virtual camera appears in the call app's camera list: the app can see it, but this proves nothing about the image yet.
• The call app's own camera preview shows your cropped framing: video is passing from OBS to the app correctly. Some apps mirror their self-view, which doesn't affect what others see.
• Other participants see the same framing clearly: only a real or test call confirms this. Network conditions and the app's compression affect sharpness, and a local preview can't show that.

Cropping to a circle or other shape

Crop/Pad and transform cropping only cut straight edges. For a round or rounded webcam overlay, add an Image Mask/Blend filter to the webcam source and point it at a mask image you supply, such as a white circle on a transparent or black background. The source then shows only through the masked area. You still need a separate image file for the shape. A rectangular crop first usually makes the mask easier to line up, since it removes the edges you don't want.

Gaps and limitations

• No version-specific documentation or test results were provided, so exact menu wording and default shortcuts may differ in your OBS build.
• No crop sizes, resolutions or quality thresholds are recommended, because none were supplied as evidence and the right values depend on your camera and framing.
• Cropping in OBS affects only OBS output. It does not change the camera's own field of view, and it does not affect apps that use the webcam directly.