Convert to MP4 (H.264)
The format that plays everywhere. Encoded on your device, not uploaded to a server.
Try it →Starts instantly · nothing uploaded
Convert your video without the upload.
It never leaves your device.
Most converters make you upload first — that's the slow part. OpenConvertVideo works right in your browser, so conversion starts the moment you pick a file. No account, no size limit, and your video never touches a server.
Convert a video →- ✓ No upload wait
- ✓ Nothing leaves your device
- ✓ Free, no account
- ✓ No artificial size limits
We can't see your files. There's no server.
Most online converters upload your file to a server, convert it there, and — they say — delete it afterward. You have to take their word for it. OpenConvertVideo works differently: everything runs locally, using ffmpeg compiled to WebAssembly, right inside this browser tab. There's no upload step, because there's no server to upload to. Open your browser's Network tab during a conversion and you'll see it for yourself — nothing goes out.
That's what makes it safe for medical footage, family videos, or confidential work files — anything you'd rather not hand to a server you don't control.
Everything you need, done locally
Pick a use case to jump straight into the converter.
Convert to H.265 (HEVC)
Same picture quality as H.264 at about half the file size. Good for storage and Apple devices.
Try it →Convert to WebM (VP9)
Open, web-friendly video. Usually smaller than H.264 at the same quality.
Try it →Compress video
Shrink a large file without wrecking the picture. No upload wait, no size cap.
Try it →Video to GIF
Turn any clip into a GIF. Control size and frame rate to keep the file small.
Try it →Understand your video
Plain-English guides on formats, codecs and compression. See all guides →
Is It Safe to Convert Video Online? What Actually Happens to Your File
Every converter site claims your files are safe. Here's how to actually check any of them — including this one — in under a minute.
Read →What Is a Codec? A Plain-English Guide to Video Compression
The one concept that explains why video files behave the way they do — codecs, in language that doesn't assume you're an engineer.
Read →Containers vs Codecs: Why Your Video Won't Play (and How to Fix It)
MP4, MKV, MOV, H.264, HEVC — which of these is the file, which is the video, and why the difference is the reason your clip won't open.
Read →Frequently asked questions
- Is OpenConvertVideo really free?
- Yes — free, with no account, no hidden tier, and no watermark on your video. It's paid for by ads and the occasional Ko-fi tip, not by your data.
- Are my files safe? Does anything get uploaded?
- Nothing is uploaded, ever. Conversion happens inside your browser using WebAssembly ffmpeg — open your browser's Network tab while converting and you'll see no outgoing file. Your video never leaves your device.
- What video formats are supported?
- Bring in almost anything your browser can open — MP4, MOV, MKV, WebM, AVI, and more. Convert to MP4 (H.264 or H.265), MKV, MOV, WebM (VP9), or GIF, plus audio-only MP3, WAV, FLAC, OGG, or M4A. One-click presets handle WhatsApp, Instagram, and email for you.
- Is there a file size limit?
- No imposed limit. Since nothing uploads, there's no server-side cap — the only ceiling is your device's own memory. (WhatsApp and email have their own limits, around 16 MB and 20–25 MB, which the built-in presets are tuned for.)
- Which browsers are supported?
- Chrome, Edge, and other Chromium-based browsers work best. Firefox works too. Safari needs version 15.2 or later.
- How fast is the conversion?
- There's no upload wait, so it starts the moment you pick a file — even a 500 MB video begins converting right away instead of sitting in a queue. Common formats like MP4, MOV, MKV, and WebM use your browser's built-in encoder, which is usually hardware-accelerated. Less common formats, like AVI or WMV, use a software encoder — slower, but you still skip the upload.
Free, fast, and always private.
If this saved you the upload wait — and kept your files off someone else's server — a coffee helps keep it running.