Video Converter: How to Convert Video Files Between MP4, AVI, MOV, and MKV for Any Device

Nothing’s more frustrating than downloading a video and discovering your device won’t play it. Different devices and platforms support different video formats — MP4 plays everywhere, while MKV and AVI may need special software. Our free Video Converter handles all major formats so your videos play on any device.

Video Formats Explained

FormatBest ForDevice CompatibilityCompression
MP4Universal playbackExcellent (all devices)H.264 / H.265
AVIOlder Windows PCsGood (Windows), Limited (mobile)Minimal (large files)
MOVApple ecosystemGood (Apple), Limited (Windows)H.264 / ProRes
MKVHigh-quality archivesLimited (needs VLC/Plex)Any codec
WebMHTML5 video on webGood (modern browsers)VP8 / VP9
WMVOlder Windows MediaGood (Windows), Poor (others)Windows Media Video

When to Convert Video Formats

Uploading to Social Media

YouTube, Instagram, TikTok, and Facebook all prefer MP4 with H.264 codec. Other formats will be re-encoded by the platform anyway, so converting upfront saves time and preserves quality control.

Watching on TV or Streaming Devices

Smart TVs, Roku, Apple TV, and Chromecast all support MP4/H.264 natively. MKV files need to be converted or streamed through a media server like Plex. Use our Video Converter to convert MKV to MP4 quickly.

Editing in Video Software

Adobe Premiere, Final Cut Pro, and DaVinci Resolve work best with specific formats. MOV (ProRes) for Apple editors, MP4 (H.264) for general use. Converting to an editing-friendly format before you start saves rendering issues.

Video Codec vs Container: What’s the Difference?

Many people confuse video formats (containers) with codecs:

  • Container (.mp4, .mkv, .avi): The “wrapper” that holds video, audio, and subtitle streams
  • Codec (H.264, H.265/HEVC, VP9): The compression algorithm that encodes the video data

An MP4 file usually uses H.264 codec, but it could use H.265. Our converter handles both — you can choose the codec during conversion for the best balance of quality and file size.

File Size Comparison

Format / CodecFile Size (10 min 1080p)QualityUse Case
MP4 / H.264~500 MBExcellentBest all-rounder
MP4 / H.265 (HEVC)~250 MBExcellentSmaller files, newer devices only
MKV / H.264~500 MBExcellentArchives with subtitles
AVI / Uncompressed~4 GBPerfectUncompressed archival
WebM / VP9~250 MBExcellentWeb optimization

Frequently Asked Questions

Does converting video reduce quality?
Yes — every time you re-encode a video (transcode), you lose some quality due to compression. To preserve quality, convert at a high bitrate or use lossless settings when possible.

Why won’t my iPhone play AVI files?
iOS doesn’t support AVI natively. Convert to MP4/H.264 using our Video Converter for full iPhone compatibility.

What’s the best format for YouTube uploads?
MP4 with H.264 codec, AAC audio, 16:9 aspect ratio, and as high a bitrate as practical. YouTube recommends at least 50 Mbps for 4K uploads.

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