How to Crop a Source in OBS Studio

Sep 8

5 min read

Updated: 6 days ago

Cartoon gloved hands cutting along dotted crop lines around a landscape image to illustrate cropping a source in OBS Studio How to Crop a Source in OBS Studio

Knowing how to crop a source in OBS Studio is one of those small skills that becomes surprisingly useful once you start designing more complicated stream layouts.

For example, maybe you downloaded or created a stream overlay with a square or rectangular space designed for your webcam. You add your camera to OBS, try dragging the edges to make it fit, and instead of cutting away the parts you don't need, OBS keeps resizing the entire camera.

That's because resizing and cropping are two different things in OBS Studio.

Cropping lets you remove part of a source from view without simply shrinking the whole thing. That makes it incredibly useful for webcams, window captures, game captures, display captures, videos, and other sources that need to fit neatly into a particular area of your stream design.

Fortunately, cropping a source in OBS only takes a few seconds.

How Do I Crop a Source in OBS?

The quickest way to crop a source in OBS Studio is to use the crop shortcut directly inside the Preview window.

Select the source you want to crop in the Sources panel.
Click the source in your OBS Preview so that the red bounding box appears around it.
On Windows or Linux, hold Alt.
On Mac, hold Option.
While holding the key, click and drag one of the red handles around the source.
Drag inward until the unwanted part of the source disappears.
Release the mouse and then release Alt or Option.

That's it.

Normally, dragging the red handles resizes the source. Holding Alt on Windows/Linux or Option on macOS changes that action from resizing to cropping. OBS changes the affected border from red to green while you're cropping, which gives you a visual indication that you're cutting away part of the source instead of resizing it.

You can crop from the left, right, top, or bottom independently.

What Is the OBS Crop Shortcut?

The OBS crop shortcut is:

Windows/Linux: Hold Alt while dragging a source's border.

macOS: Hold Option while dragging a source's border.

There isn't a separate keyboard command that automatically crops the source. Alt or Option modifies what happens when you drag the source's bounding box.

This works especially well when you're visually designing your scene because you can watch the crop happen in real time.

How Do I Change the Source Size in OBS Studio?

If you actually want to resize a source instead of crop it, select the source and simply drag its red corner or edge handles without holding Alt or Option.

OBS describes the red outline around a selected source as its bounding box. Dragging its handles normally changes the source's size, while holding the crop modifier changes which portion of the source remains visible.

This distinction is particularly important when you're fitting something into a stream overlay.

For example, shrinking a 16:9 webcam feed to fit inside a narrow vertical frame may make the entire camera feed smaller than you want. Cropping allows you to remove the excess space from the sides while keeping yourself large enough to fill the frame.

You can then resize and reposition the cropped source until everything fits.

Can You Crop a Window Capture or Game Capture in OBS?

Yes.

The same basic cropping technique can be used with many visual sources in OBS, including:

Window Capture
Game Capture
Display Capture
Video Capture Devices such as webcams and capture cards
Images
Media Sources

This means you could capture an application window but remove its menu bar, crop unnecessary portions of a game capture, or trim a webcam feed to fit a custom overlay.

OBS supports several different visual source types, including Window Capture, Game Capture, Display Capture, Video Capture Devices, images, and media sources.

How to Crop a Source Using Edit Transform

You don't have to crop by dragging the source manually.

For more precise control, OBS also lets you enter crop values through Edit Transform.

Select your source, then go to:

Edit → Transform → Edit Transform

You can also right-click the source and access its Transform options.

The Edit Transform window gives you much more precise control over source positioning, sizing, and cropping than dragging everything by eye. OBS lists Ctrl+E on Windows/Linux and Command+E on macOS as the shortcut for opening Edit Transform.

This is useful when you're building a layout and need several elements to line up precisely.

What Is the OBS Crop/Pad Filter?

OBS also includes a Crop/Pad filter.

Right-click your source, choose Filters, add an Effect Filter, and select Crop/Pad.

This lets you specify exactly how many pixels should be removed from the left, top, right, and bottom of a source.

There is one important difference between this method and simply cropping the source inside your scene.

According to OBS, cropping through the Crop/Pad filter changes the base source, meaning the crop can affect every instance of that source across your scenes. Cropping through Transform applies to that particular source instance instead.

For everyday stream layout design, I usually find the Alt/Option drag method much faster.

Crop, Resize, and Position Until Your Source Fits

Once you understand the difference between cropping and resizing, arranging sources inside OBS becomes considerably easier.

Remember the basic formula:

Drag = resize.

Alt + drag on Windows/Linux = crop.

Option + drag on Mac = crop.

You can crop away the portions you don't want, resize what's left, and move the source into position.

It's a very simple OBS feature, but when you're creating layered scenes, fitting cameras inside custom frames, or designing your own stream layouts, it becomes one of those little tools you'll use constantly.