Video Resizer & Cropper

Drop the file onto this page, choose a target resolution — 1080p, 720p, or an exact width and height — and press Convert. FFmpeg is compiled to WebAssembly and runs inside the tab, so the video never leaves your machine. There is no queue or watermark; whether a very large file can finish still depends on browser memory.

Switch to Crop, then drag the box over the preview to the region you want to keep and pull its handles to resize it. The lock chips hold the box to 1:1, 16:9, 9:16, and other common shapes, and the four fields take exact pixel values. The area outside the box is discarded, and the output is the size of the box unless you scale it afterwards.

Choose Aspect ratio, pick 9:16, and decide how the picture fits. "Crop to fill" fills the vertical frame and cuts the sides off — drag the box onto whoever is talking. "Fit with bars" keeps the whole frame and fills the space above and below with either a flat colour or an enlarged, blurred copy of the video. The latter makes a landscape clip feel more at home in a vertical frame.

Some, unavoidably. Changing the frame geometry means decoding and re-encoding every frame, so the result is one encode further from the original. Scaling down is the gentler direction — there are simply fewer pixels to describe — while scaling up cannot recover detail that was never recorded. The quality setting decides how much is given up in the re-encode: High for footage that will be edited further, Smaller file for something being sent or posted.

Vertical feeds such as Reels, TikTok, and Shorts commonly use 9:16, for example 1080×1920. A square post is often 1080×1080, and the taller 4:5 shape at 1080×1350 uses more of a phone screen. 16:9 is the usual shape for YouTube and most players: use 1920×1080, or 1280×720 for a smaller file. Pick the ratio here and set the short side to 1080 to produce those common dimensions.

No. The engine is FFmpeg compiled to WebAssembly and it runs inside your browser tab. The file is read from disk into the tab's memory and the result is written back out as a download. Nothing about the file crosses the network, which you can confirm by watching the network panel while a render runs.

Crop when there is a clear subject and the edges of the frame are not carrying information — a person talking, a product, a face. Add bars when nothing can be lost: a chart, a slide, a full-screen interface walkthrough, or anything with text near the edges. Bars cost you screen area, cropping costs you picture; the wrong one is obvious to a viewer either way.

Every frame is decoded, scaled, and encoded again on a single thread in the tab, so the time scales with the length, the resolution, and your machine — a short clip is quick, a long high-resolution recording is not. The practical ceiling is memory rather than time: the whole file is held in the tab while it works, so beyond roughly 250 MB things become unreliable. Cutting the section you need out first keeps both numbers down.

No, and no tool can. A compressed video stores frames at one specific pixel grid; changing that grid means decoding the frames, resampling them, and encoding them again. Copying streams untouched — which the trimmer does — only works when the picture itself is left alone. That is why cutting a clip is instant and resizing one is not.

H.264 in its usual 4:2:0 form stores one colour sample for every 2×2 block of pixels, so an odd width or height has no way to describe its last row or column of colour. Encoders reject those dimensions outright. This tool rounds every dimension — and every crop offset — to an even number and shows you the result, rather than letting the encoder fail or silently shift the colour planes.