Why does my trimmed clip start a second earlier than I set it?

Lossless cutting can only start at a keyframe. If your chosen start point falls between keyframes, the cut snaps back to the nearest earlier keyframe. Videos with sparse keyframes (long GOPs) show this most.

Can I trim a video without uploading it anywhere?

Yes. Minitooler's Video Cutter runs FFmpeg compiled to WebAssembly inside your browser tab, so the file never leaves your device — no upload, no server, no queue.

What formats can be cut losslessly?

MP4, MOV, MKV and WebM are all supported. H.264, H.265/HEVC, VP9 and AV1 video with AAC, MP3 or Opus audio can be stream-copied into a trimmed file.

Is there a file size limit?

Free use is capped for fair use; Pro removes Minitooler's own limits, leaving only what your browser and device memory allow. Large 4K files work best in a desktop browser.

How to Cut a Video Without Losing Quality (Lossless)

The one thing that decides whether you lose quality

A video file is not a sequence of pictures. It's a container (MP4, MOV, MKV, WebM) wrapping already-compressed streams — usually H.264, H.265/HEVC, VP9 or AV1 video plus AAC, MP3 or Opus audio. When you cut a clip, there are only two possible strategies:

Re-encode. Decode every frame back to raw pixels, then compress them again. Slow, CPU-hungry, and lossy: you're compressing an already-compressed image, so fine detail, gradients and text edges degrade every single time.
Stream copy (lossless). Leave the compressed data untouched and simply write the byte ranges you want into a new container, fixing timestamps as you go. Near-instant, and the output is bit-for-bit identical to the source in the range you kept.

If a tool takes several minutes to trim a 30-second clip, it re-encoded. If it finishes almost as fast as it can read the file, it stream-copied. For simple "cut out the middle two minutes" jobs, there is no good reason to re-encode.

The catch: keyframes

Lossless cutting can only begin at a keyframe (I-frame) — a fully self-contained frame. Every other frame is described as a difference from its neighbours, so it is meaningless without the keyframe it depends on. Encoders typically place a keyframe every 2–10 seconds.

So if you ask for a cut at 00:12.4 and the nearest earlier keyframe sits at 00:10.0, a lossless cut gives you 2.4 extra seconds at the front. That's the trade: perfect quality with a small snap, or frame-exact timing with re-encoding. In practice, for clipping gameplay, trimming dead air off a screen recording, cutting an interview segment or shortening a video to fit an upload limit, the snap is irrelevant.

Rule of thumb: need it perfect-looking? Go lossless. Need it frame-exact for editing? Take it into a real NLE and re-encode once, at the end.

How to do it in your browser, in about a minute

Open the Video Cutter and drop your file in. It loads locally — there's no upload progress bar because there's no upload.
Scrub the timeline and set your start and end points.
Export. The trim is done with FFmpeg compiled to WebAssembly, using stream copy, so the clip is written out at original quality.

The whole thing happens inside the browser tab. That matters more than it sounds: unreleased footage, client work, screen recordings full of internal dashboards, medical or legal video, and anything under NDA should not be uploaded to a free website in exchange for a trim.

Trim a video losslessly, right now

Drop in an MP4, MOV, MKV or WebM, pick your in and out points, and download the trimmed clip. Runs entirely in your browser — nothing is uploaded.

Try it with your own file

The alternatives, honestly compared

Cloud trimmers (Clideo, Kapwing, VEED, Online Video Cutter and friends)

These are the results that dominate page one. They work, but the model is the problem: your file is uploaded to their servers, processed there, and sent back. That means a long upload for anything big, a queue at peak times, a watermark or a sign-up wall on the free tier, hard file-size caps (often 500 MB–1 GB), and — the deal-breaker for a lot of people — your video sitting on someone else's infrastructure under a retention policy you didn't read. Most of them also re-encode by default, so you pay in quality for the privilege.

LosslessCut (desktop)

Genuinely excellent, and the reference implementation of this idea. It's free, open source, and does keyframe-accurate lossless cutting with a proper segment workflow. The only downside is that it's an install: a ~150 MB desktop app you have to download, unblock on locked-down work machines, and update. If you cut video daily, install it. If you need to trim one clip on a borrowed laptop, a browser tab wins.

FFmpeg on the command line

The thing every other tool is wrapping. ffmpeg -ss 10 -to 40 -i in.mp4 -c copy out.mp4 is exactly the operation described above, and it's free and perfect. It's also a command line, with argument-order gotchas around -ss placement that silently change whether your cut is accurate or fast. Great if you already live in a terminal; a bad recommendation for everyone else.

QuickTime, Photos, and the Windows video editor

Fine for a quick top-and-tail on your own machine. QuickTime's trim is lossless for supported formats but only handles MOV/MP4 and gives you almost no control. The Windows Photos editor re-encodes, slowly, and often drops quality noticeably. Neither handles MKV at all.

Premiere, DaVinci Resolve, CapCut

Full editors. If you're actually editing — titles, colour, multiple tracks — use them. Using a 20 GB NLE install and a full export to remove eight seconds from the start of a screen recording is not a workflow, it's a punishment.

Where Minitooler's Video Cutter fits

No upload, ever. Your file is read from disk by the browser; it never touches a server. Same privacy guarantee as a desktop app, no install.
No watermark, no account for a first look. Free use covers occasional trims; Pro at $5/month removes Minitooler's limits across every tool.
Lossless by default for MP4, MOV, MKV and WebM.
Works offline once the page has loaded — handy on a plane or a locked-down network.

Related tools you'll probably want next

Video to GIF — turn the clip you just cut into a shareable GIF.
Video to Audio — pull the MP3 or WAV out of a recording.
Video Thumbnail Generator — grab frames or a contact sheet from the same file.
Browse all Minitooler tools

FAQ

Does cutting a video always reduce its quality?

No — only re-encoding does. A lossless cut copies the existing compressed streams into a new file, so what you keep is bit-for-bit identical to the source.

Why does my trimmed clip start slightly earlier than I set it?

Because a lossless cut has to start on a keyframe. If your in-point falls between keyframes, it snaps back to the nearest earlier one. Videos with long gaps between keyframes show this most.

Can I trim a video without uploading it?

Yes. The Video Cutter runs FFmpeg in WebAssembly inside your tab, so the file stays on your device.

Which formats can be cut losslessly?

MP4, MOV, MKV and WebM, with H.264, H.265/HEVC, VP9 or AV1 video and AAC, MP3 or Opus audio.

How big a file can I trim?

Free use is capped for fair use; Pro removes Minitooler's own limits, leaving only your browser and device memory. Large 4K files are happiest in a desktop browser.

Is it really free?

Yes for everyday use. Because everything runs on your hardware, there are no server costs to pass on — see pricing if you want unlimited use across every tool.