Video Resizer
Enter your video dimensions and target platform to get the correct output size, bitrate recommendations, and FFmpeg command to resize it.
Use the Video Resizer
Source Video Dimensions
Letterbox / pillarbox to fit inside target without cropping.
Enter source dimensions and press Calculate Resize
Output Dimensions
Source
3840 × 2160
16:9
Output
1920 × 1080
16:9
Aspect Ratio Preview
Source
Output
Recommended Bitrates
Video (H.264)
5 Mbps
Video (H.265)
2.5 Mbps
Audio (AAC)
192 kbps
FFmpeg Command
HandBrake CLI Command
Summary
Video Resizer is a client-side calculator that takes your original video dimensions and target platform or custom resolution, then computes the correct output dimensions while preserving the original aspect ratio. It also recommends video and audio bitrates for the chosen resolution and generates a ready-to-run FFmpeg or HandBrake command you can paste directly into a terminal. No file upload required — all math happens in your browser.
How it works
- Enter the width and height of your original video (e.g. 3840 x 2160).
- Choose a target platform preset or enter a custom target width or height.
- The calculator preserves the original aspect ratio and shows the exact output dimensions.
- Review the recommended video bitrate, audio bitrate, and codec for the target resolution.
- Copy the generated FFmpeg or HandBrake CLI command and run it in your terminal.
Use cases
- Resize a 4K recording down to 1080p before uploading to YouTube.
- Scale a vertical phone video (9:16) to the correct size for Instagram Reels.
- Check what resolution a widescreen 21:9 source becomes at 1080p height.
- Prepare a video for Twitter/X, TikTok, LinkedIn, or Facebook with correct dimensions.
- Get a precise FFmpeg scale filter command without guessing dimensions by hand.
- Verify output dimensions before a long encode to avoid wasting time.