How to Change Screen Recording Canvas Size & Aspect Ratio on Mac

When you record your screen on Mac using standard utilities, it captures the exact aspect ratio of your monitor (usually 16:9 or 16:10). But if you are creating vertical videos (9:16) for TikTok, Shorts, or custom crops for slide decks and courses, a wide monitor layout does not fit.

Editing this in post-production with tools like Premiere Pro or Final Cut requires cropping and zooming, which can blur your text.

Here is how to set up and record custom aspect ratios natively on macOS.

Method 1: Resize Your Web Browser or App Window

If you are recording web-based content, the simplest trick is to resize your browser window to your target aspect ratio:

1. Drag your browser window to make it narrow and tall (for vertical layouts).
2. Open your screen recorder.
3. Select Record Selected Window instead of recording the entire screen.
4. Select the browser window. The resulting video will crop to the window boundaries.

Method 2: Scale Your Mac Monitor Resolution

If you need your entire desktop to scale, you can change your monitor's display resolution in macOS settings:

1. Go to System Settings > Displays.
2. Select a resolution that matches your target layout (e.g., 1080p for standard landscape).
3. Record the display.

The Modern Solution: Built-in Canvas Inspectors

Resizing windows or changing system displays is an annoying workaround.

With ScreenKite, you can adjust your layout in the editor. You can record your standard screen, and then choose a vertical aspect ratio in the inspector. The app automatically frames the cursor and adds custom background padding, ensuring your text remains sharp and perfectly readable in the new aspect ratio.