Which output should I choose for maximum compatibility?

MP4 with H.264 video and AAC audio plays on everything made in the last 15 years.

Why is some conversion instant and another slow?

Instant means the video stream was copied into a new container. Slow means it had to be re-encoded — the target codec differed or a resolution change was requested.

Which files go to the server?

AVI, WMV and any file whose codec the browser cannot decode. The page indicates this before starting; server files are deleted within an hour.

Video Converters

Video Converter

The general-purpose tool: pick an output container and codec, set resolution and frame rate, burn in subtitles or strip audio. Standard files convert in your browser; legacy ones go through our server.

Runs in your browser when it can; large or unusual files use our EU server and are deleted within 1 hour.

Drop supported files here

or click to browse · paste from clipboard · up to 8000 MB each

Select files

Options

Convert to

Quality

Resolution

Audio

About Video Converter

When the one-to-one pages do not cover your case — MP4 to MKV with two audio tracks, MOV to WebM, WMV to MOV — this converter exposes the full set of options.

Streams are copied whenever the target container supports them (no loss), and re-encoded only when necessary. Legacy codecs (DivX, WMV, DV) cannot be decoded by browsers and are converted on the server.

How it works

Drop your files onto the box above, click it to browse, or paste from the clipboard.
Adjust the options if you need to — the defaults suit most cases.
Press Convert. Small files are handled on your device; larger ones are sent to our server with a progress bar.
Download the result — individually or all at once.

About the formats

MP4 · MPEG-4 Part 14 video · .mp4

The video format that works everywhere: phones, TVs, browsers, social networks. Normally H.264 video with AAC audio.

MP4 is a container; the codec inside (H.264, HEVC/H.265, AV1) decides what can play it.
H.264 MP4 is the safe choice for uploads and sharing; HEVC MP4 from newer iPhones needs extra codecs on Windows.
The “moov atom” placement decides whether a browser can start playing before the whole file downloads.

MOV · QuickTime movie · .mov

Apple’s QuickTime container, the default for iPhone videos and Mac screen recordings; very close to MP4 but not accepted everywhere.

MOV and MP4 share the same underlying structure, so MOV to MP4 usually only needs repackaging, not re-encoding.
iPhone MOV files are often HEVC (H.265) with HDR, which Windows and many web apps cannot play without conversion.
Screen recordings on Mac are MOV with H.264 and can be very large.

MKV · Matroska video · .mkv

An open container that can hold any codec plus multiple audio tracks, subtitles and chapters; popular for rips and downloads, unsupported by iPhone and many TVs.

MKV to MP4 keeps the video quality when the codec is H.264 or HEVC — only the container changes.
MP4 cannot carry every MKV feature: soft subtitles and some audio codecs (e.g. DTS) must be converted or dropped.
Most desktop players (VLC, MPV) play MKV; Safari, iOS and PowerPoint do not.

WebM · WebM video · .webm

The royalty-free web video format (VP8/VP9/AV1 video, Vorbis/Opus audio) produced by browser screen recorders, Discord and many online tools.

WebM is based on Matroska and plays in every browser, but not in iMovie, Premiere or on most phones without conversion.
Browser recording APIs output WebM, which is why screen recordings from web apps come as .webm.
WebM to MP4 requires re-encoding the video, because MP4 does not carry VP9 widely.

Related conversions

More in Video Converters · All converters