Best Video Size for Instagram Reels and YouTube Shorts

The best video size for Instagram Reels and YouTube Shorts is usually 9:16 vertical. That does not mean every source video should be blindly cropped to 9:16.

The practical goal is to make the clip feel native on a phone while keeping the subject, captions, and important details visible.

Quick size guide

Use 9:16 for TikTok, Instagram Reels, YouTube Shorts, and most vertical social clips. Use 1:1 for square posts. Use 4:5 for feed-first vertical posts. Use 16:9 for YouTube, websites, webinars, and widescreen playback.

In the free video resizer, these are handled as presets so you can switch between platform shapes without rebuilding the edit.

Most sizing mistakes happen because people treat dimensions as a checklist. The export can be exactly 1080x1920 and still fail if the caption sits under platform buttons or the speaker's face is cropped too tightly.

9:16 for Reels, Shorts, and TikTok

Vertical 9:16 is the default for phone-first short-form platforms. It fills the screen and gives viewers the least friction.

If your source video was already filmed vertically, resizing is straightforward. If the source is widescreen, you need to choose between crop-to-fill and padding.

Crop-to-fill feels native, but it removes side content. Blur background or solid background keeps the whole frame visible, but it can feel less immersive. Choose based on the content, not a fixed rule.

1:1 for square posts

Square video is useful when you want a post that works in feeds and embeds without committing to full vertical. It gives you more width than 9:16 and more height than widescreen.

Square works well for simple talking-head clips, quotes, product demos, and short educational videos. It is less ideal when a platform strongly favors full-screen vertical viewing.

4:5 for feed video

4:5 is a tall feed-friendly frame. It gives you more screen space than square while still feeling less aggressive than full vertical.

Use 4:5 when the clip is intended for a feed placement and you want a little more room for captions, title text, or product visuals.

16:9 for widescreen video

Use 16:9 for YouTube long-form, webinars, website embeds, and screen recordings. It keeps horizontal layouts readable and avoids cutting off slides or interface elements.

If you are making both long-form and short-form versions, export separate sizes. Do not rely on one file to serve every platform perfectly.

Safe areas matter more than exact numbers

Even when the video size is correct, the composition can still fail. Platform buttons, captions, usernames, and descriptions may cover parts of the frame. Keep faces, captions, product details, and important text away from the extreme edges.

This is why a vertical clip should be reviewed as a vertical clip, not only as a file with the right dimensions. Watch it at phone size. If the subject feels too low or captions collide with platform UI, adjust the layout before publishing.

For talking-head content, keep the face comfortably above the caption area. For screen recordings, increase the visible margin so menus and labels do not become unreadable. For product clips, leave enough space around the object so the video does not feel accidentally cut off.

Crop or resize?

Use Crop Video when you want to choose exactly which part of the frame remains. This is useful when a person is off-center, when you need to remove empty space, or when you want a tight social crop.

Use Video Resizer when you need a platform canvas and want options like blur background, solid background, or crop-to-fill. Resizing is usually better when the full original frame still matters.

If the source is a polished horizontal video, resizing with a background can preserve the original framing. If the source has empty space or the subject is small, cropping may create a stronger clip. The tradeoff is simple: crop gives focus, resize protects context.

Captions and safe areas

Captions need room. A clip can have the correct dimensions and still be hard to watch if captions sit too low, cover a face, or run too wide.

After resizing, add or check captions in the final frame. The auto subtitle generator is a better step after the visual size is decided, because line breaks and placement depend on the output frame.

Related tools and guides

• Resize videos with Video Resizer
• Crop a specific frame with Crop Video
• Add captions with the auto subtitle generator
• Make clips from longer recordings with Long Video To Clips
• Learn how to resize video for TikTok

FAQ

What is the best size for Instagram Reels?

Use 9:16 vertical for most Reels.

What is the best size for YouTube Shorts?

Use 9:16 vertical for most Shorts.

Should I crop horizontal video to vertical?

Only if the important subject remains visible. Otherwise use blur or solid background resizing.

What size should I use for feed posts?

Use 1:1 for square posts or 4:5 when you want a taller feed layout.

Should captions be added before resizing?

Usually no. Resize first, then place captions in the final frame.