Aspect Ratio Tools (Fit, Fill, BlurPad)

What it does

Fit (Letterbox): keep full picture, pad to frame.
Fill (Crop): scale then crop to fill exact size.
BlurPad: a tasteful blurred background behind the video.
Presets for 1920×1080, 1080×1920, 1080×1080, 1080×1350, and more.

Great for YouTube, Instagram, TikTok, Shorts, Reels, stories, and ad specs.

FFmpeg Aspect Commands (Copy-ready)

Fit (Letterbox) to 1920×1080

ffmpeg -i input.mp4 -vf "scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2:color=black" -c:v libx264 -crf 21 -preset veryfast -c:a copy output-fit-1920x1080.mp4

Change color=black to a hex (e.g., color=#101318).

Fill (Crop) to 1920×1080

ffmpeg -i input.mp4 -vf "scale=1920:1080:force_original_aspect_ratio=increase,crop=1920:1080" -c:v libx264 -crf 21 -preset veryfast -c:a copy output-fill-1920x1080.mp4

BlurPad to 1080×1920 (vertical)

ffmpeg -i input.mp4 -filter_complex "[0:v]scale=1080:1920:force_original_aspect_ratio=increase,boxblur=30:1,crop=1080:1920[b];[0:v]scale=1080:1920:force_original_aspect_ratio=decrease[fg];[b][fg]overlay=(W-w)/2:(H-h)/2" -c:v libx264 -crf 21 -preset veryfast -c:a copy output-blurpad-1080x1920.mp4

Adjust boxblur=30:1 for stronger/weaker blur.

Fit to 1080×1080 (Square)

ffmpeg -i input.mp4 -vf "scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2:color=black" -c:v libx264 -crf 21 -preset veryfast -c:a copy output-fit-1080x1080.mp4

Fill to 1080×1350 (4:5 Portrait)

ffmpeg -i input.mp4 -vf "scale=1080:1350:force_original_aspect_ratio=increase,crop=1080:1350" -c:v libx264 -crf 21 -preset veryfast -c:a copy output-fill-1080x1350.mp4

Stretch (no preserve AR) to 1920×1080

ffmpeg -i input.mp4 -vf "scale=1920:1080" -c:v libx264 -crf 21 -preset veryfast -c:a copy output-stretch-1920x1080.mp4

Note: This distorts the image; prefer Fit/Fill/BlurPad.

Tip: swap libx264 for libx265 (HEVC) or libsvtav1 (AV1) if desired, and tweak -crf for quality/size. Use -preset to balance speed vs compression.

Why editors use this

Spec-perfect outputs: hit exact frames for every platform.
Consistent look: letterbox/blurpad without guesswork.
Copy-ready commands: replicate locally in pipelines.

Also try Web-Ready or generate frames with Thumbnails.

FAQ

Is the aspect tool free?

Yes — no sign-up required. Upload, pick a mode/preset, download the result.

Which presets are supported?

16:9 (1920×1080, 1280×720), 9:16 (1080×1920), 1:1 (1080×1080), 4:5 (1080×1350), plus custom.

Fit vs Fill vs BlurPad?

Fit pads to the target size (no cropping). Fill crops to fill the frame. BlurPad uses a blurred background behind the full picture.

Can I change background colour and quality?

Yes. Choose any hex colour for Fit/BlurPad. Use the quality slider (CRF) to balance size vs quality. Lower CRF = higher quality.

Which formats are supported?

Anything FFmpeg can decode: MP4, MOV, M4V, MKV and more.

Try it now

Open Aspect Tools, choose Fit/Fill/BlurPad, pick a preset, and export.

Open Aspect Tools →

Prefer the command line? Copy any command above and run it locally with FFmpeg.