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Video Aspect Ratio Converter

Reformat your video for any platform. Get exact crop or letterbox dimensions for YouTube, TikTok, Reels, and more.

100% browser-based — your inputs never leave your device. Just a calculator, no upload required.

Source video

Source ratio: 16:9 (1.778 decimal)

Target platform

Visual comparison

Source
16:9
→
Target
9:16

Option 1: Crop

608 × 1080

Trim 656px from each side (left + right)

Keeps all output pixels at target ratio. Lose some source content but fills the entire output frame.

Option 2: Letterbox

1080 × 608

Add 656px black bars on top and bottom (letterbox)

Keeps every source pixel. Adds black bars to reach the target frame. Best for content with important edges.

Target details

PlatformTikTok
Aspect ratio9:16
Recommended1080×1920
Vertical short-form

How to use

  1. 1.Enter your source video dimensions
  2. 2.Pick the target platform
  3. 3.Choose to crop (lose pixels) or letterbox (add bars)
  4. 4.Use the dimensions in your editor or ffmpeg

When to use what

  • Crop — vertical clips for TikTok/Reels where subject is centered
  • Letterbox — when text or edges matter (landscape shots, infographics)
  • Resize only — when source and target ratios already match

Frequently Asked Questions

How do I convert a 16:9 video to 9:16 for TikTok?+
You have two choices: crop the sides of the horizontal video to fit vertical (loses content on left and right) or letterbox it (keeps everything but adds black bars top and bottom). For TikTok, cropping the focal subject usually looks more native.
What's the difference between letterboxing and pillarboxing?+
Letterboxing adds black bars to the top and bottom (wide content in a narrower frame). Pillarboxing adds black bars to the left and right (narrow content in a wider frame). The names come from old TV broadcasting.
What aspect ratio should I use for YouTube?+
YouTube's primary player is 16:9. Upload at 1920×1080 (1080p), 2560×1440 (1440p), or 3840×2160 (4K) for best results. YouTube Shorts use 9:16 vertical at 1080×1920.
Does this tool actually crop my video?+
No — it's a calculator that tells you what dimensions to use. To actually crop or letterbox, use a video editor like DaVinci Resolve, Premiere, Final Cut, CapCut, or ffmpeg with the calculated values.
What's the best ratio for Instagram Reels?+
Instagram Reels use 9:16 vertical at 1080×1920. The same dimensions work for TikTok and YouTube Shorts, so you can post the same export across all three platforms.
When should I crop instead of letterbox?+
Crop when keeping your subject centered in the new frame matters more than preserving every pixel — typical for short-form vertical content. Letterbox when content at the edges is important, such as text, motion graphics, or wide landscape shots.

Learn more

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