How to Crop a Screen Recording on Mac: Region, Trim & Resize

The most efficient approach is to define the capture region before you start recording, so you only capture what you need and your exported file is already the right size without any post-processing.

Press Command+Shift+5 to open the macOS screenshot toolbar. Click Record Selected Portion. A crosshair appears — drag to select the area of your screen you want to record. The selection box appears with drag handles on the edges and corners. Adjust it precisely, then click Record.

The recording captures only the pixels inside your selection rectangle. If you selected a 1200x800 region, the output file is 1200x800. This is the fastest way to record just a single app window or panel without recording your entire display.

Limelight lets you define a capture region at the start of a recording session. When you click the record button in Limelight, you can choose to capture a specific window or drag to select a custom region, in addition to full-screen capture.

Limelight's region capture combines with its other features — cursor spotlight, auto-zoom on clicks, keystroke display — so you get the visual polish features applied to a focused capture area. This is useful for app demos where you want to exclude your taskbar, other windows, or desktop clutter from the recording.

QuickTime Player can trim the timeline of a recording (remove the start and end) but cannot spatially crop the video frame. To trim in QuickTime: open your recording, press Command+T or go to Edit → Trim. Yellow handles appear at both ends of the timeline. Drag the left handle to set the new start point, drag the right handle to set the new end point. Press Trim, then save.

This is a non-destructive operation within QuickTime — until you save, your original file is unchanged. When you choose File → Save, QuickTime replaces the file with the trimmed version. Use File → Export As if you want to keep the original and create a new trimmed copy.

QuickTime's trim function does not re-encode the video, making it very fast even for large files. However, the accuracy is limited to the nearest keyframe, which can leave a fraction of a second of unwanted content at the cut point.

Dead air — the seconds before you start demoing and after you stop — is the most common problem with raw screen recordings. Even three seconds of a static screen at the start signals poor production quality to viewers.

In Limelight's built-in editor, the trim handles on the timeline let you trim both ends precisely. This is often all the editing a short tutorial needs — record, trim, export.

For recordings where you need to cut sections from the middle (not just trim the ends), you need a more capable editor. iMovie's clip splitter (Command+B at the playhead position) lets you cut and delete segments. DaVinci Resolve's free tier handles multi-cut editing with more precision.

iMovie can spatially crop video — trimming the frame edges to change the aspect ratio or zoom into a portion of the recording. Import your recording into iMovie, select the clip, and click the Crop button in the top toolbar (it looks like overlapping rectangles).

Choose Crop to Fill to zoom in and crop edges, or Ken Burns to animate a zoom. Drag the selection rectangle to define what portion of the frame you want to keep. Preview in the viewer, then click Apply.

Note that cropping in iMovie re-encodes the video, which takes time and may slightly reduce quality compared to a lossless crop. For spatial crop of a small region, consider re-recording with a defined capture region instead — the quality will be better.

Changing the output resolution (resizing) is different from cropping. You might want to resize a 2560x1600 Retina recording down to 1920x1080 for file size, or convert a 16:9 recording into 9:16 for social media.

In iMovie, export at a lower resolution via File → Share → File → choose Resolution. For aspect ratio conversion (16:9 to 9:16), Limelight's built-in 9:16 export mode handles this with letterboxing during the export step. In DaVinci Resolve, create a new timeline with your target aspect ratio and drag the clip in — it adapts to the new frame.

HandBrake (free, open-source) is the best tool for pure resizing and compression without editing: open the file, set target dimensions in Picture Settings, and encode. It supports batch processing if you have multiple files.

After cropping or trimming, export as MP4 for maximum compatibility. In QuickTime: File → Export As → 1080p (or your target resolution). In iMovie: File → Share → File → choose quality. Both produce H.264 MP4 files that play on any device.

For web use, aim for files under 100MB for recordings under 5 minutes. If your export is larger, use HandBrake to compress it further with the H.264 codec at a constant quality value around RF 22-26 — this reduces file size significantly with minimal visible quality loss.