Resize Video in your browser
— fit any platform
9:16 for Reels, TikTok and Shorts, 1:1 square, 16:9 widescreen, 4:5 feed — with smart cropping. Your video never leaves your device: no upload, no watermark, no signup, no size limit.
Aspect ratio
How to fit
Options
How it works
Three steps, zero uploads.
Drop in any MP4, MOV, WebM or MKV — even a 1GB screen recording or phone video.
9:16 vertical, 1:1 square, 16:9 widescreen, 4:5 portrait or exact custom pixels — then smart crop, letterbox or stretch.
Your device's own hardware encoder does the work — usually faster than an upload would even take.
Make any video 9:16 for Reels, TikTok and Shorts
Shot in landscape but need vertical? Pick 9:16 + Smart crop and the tool scales your footage to fill a 1080×1920 frame, trimming the sides evenly — the standard treatment for Instagram Reels, TikTok and YouTube Shorts. Prefer to keep every pixel? Letterbox adds clean bars instead. The same presets cover 1:1 square, 4:5 Instagram feed and 16:9 widescreen.
Why this resizer is different
Most online resizers upload your file to a server, wait, then hand back a watermarked result — and refuse anything over a couple hundred MB. This tool uses your browser's built-in WebCodecs hardware encoding, so even a 1GB video resizes in minutes, privately, on your own machine. No watermark, no signup, no size cap.
Make any video 9:16 for Reels, TikTok and Shorts
Vertical platforms punish landscape uploads with tiny letterboxed players. Pick the 9:16 aspect here and choose how to fill the frame: smart crop keeps the center of the action and trims the sides — ideal for talking-head and gameplay footage — while letterbox keeps every pixel and pads the rest. The same two clicks produce 1:1 square for feeds, 4:5 portrait for Instagram, or classic 16:9 from a vertical phone clip. Output resolution snaps to platform-friendly sizes (1080/720/480) with even dimensions, so uploads never get rejected.
Cover, contain or stretch — pick the right fit
Three fit modes cover every case. Cover (smart crop) fills the new frame completely and crops the overflow — the polished, professional look. Contain (letterbox) shrinks the whole video to fit and fills the remainder with black bars — nothing is ever cut off, best for slides and screen recordings. Fill (stretch) forces the video into the new shape without cropping or bars — occasionally useful, knowingly distorted. Everything is processed on your device: no upload, no watermark, no account.
Frequently asked questions
How do I make a video 9:16 for Instagram Reels?
Choose the 9:16 aspect, keep the default smart crop so the center of the frame is preserved, and press Resize. You get a vertical 1080×1920-class file ready to upload.
Can I resize a video without cropping anything?
Yes — pick the Contain (letterbox) fit. The whole frame is preserved and the remaining space is padded, so nothing is ever cut off.
Is my video uploaded to a server?
No. Resizing happens entirely inside your browser on your device's own hardware. You can watch the network tab: after the page loads, nothing is sent anywhere.
How do I make a video vertical (9:16)?
Choose the 9:16 preset and Smart crop, then press Resize. You get a 1080×1920 video ready for Reels, TikTok or Shorts.
What do Smart crop, Letterbox and Stretch do?
Smart crop fills the frame and trims overflow evenly. Letterbox keeps the whole picture with black bars. Stretch distorts the image to fit exactly.
Is there a file size limit?
No hard limit. The file is streamed piece by piece, so 500MB–1GB+ works on a modern desktop. A desktop is recommended for 1GB+.
Which browsers work?
Chrome, Edge and Opera (desktop + Android) and Firefox 130+ are fully supported. Recent Safari versions work as well; older Safari may not support audio and the tool will tell you.