Video to MP4 Converter

Convert Video to MP4 Online — Free

Upload any video — MOV, MKV, WebM, AVI, FLV, WMV and 35+ more — and convert it to MP4 on our servers. Keep H.264 to preserve quality, then click Convert to get a standard MP4 that plays everywhere. Free, no watermark, and no sign-up required.

Real result: An MP4 with H.264 plays on virtually every phone, browser, editor, and TV. When the source is already H.264, the stream is preserved, so quality stays essentially identical to the original.

How to Convert Video to MP4 Online

1. Upload Your Video: Drag and drop or click "+ Add Files" to add one or more clips. Accepted inputs include MOV, MKV, WebM, AVI, WMV, FLV, MTS/M2TS, VOB, TS, 3GP, HEVC, MPG/MPEG, DV, MXF, DivX, XviD, OGV, SWF, RM/RMVB, ASF, and 15+ more — 36 formats total.
2. Pick a Quality Preset: Default is "Very High (Recommended)" which targets visually lossless H.264 output. Switch to Constant Quality (CRF) for size-vs-fidelity control (CRF 18 = near-lossless, CRF 23 = web default, CRF 28 = small file), Constant or Variable Bitrate for streaming targets, or Specific file size to cap the output (handy for Discord 10 MB or Gmail 25 MB attachments).
3. Resize and Trim (Optional): Under Video resolution, keep original, choose a preset (4K 2160p, 1440p, 1080p, 720p, 480p), scale by Resolution Percentage, or enter a custom Width × Height. Under Trim, switch from Unchanged to Time Range to clip a start/end window before encoding.
4. Convert and Download: Click Convert. Output is H.264 in an MP4 container by default — the most universally compatible video file there is. No watermark, no sign-up, no file count limit.

Why Convert to MP4?

MP4 (ISO/IEC 14496-14) is the closest thing video has to a universal file format. Pairing the MP4 container with the H.264/AVC codec gives you a file that plays natively in every major browser, every modern phone, every smart TV released in the last decade, and every social platform. Conversion is the right move when:

• Your video won't play on a recipient's device. MOV from an iPhone, MKV from a torrent, WebM from a screen recorder, and AVCHD/MTS from a Sony or Panasonic camcorder all fail on at least one major platform. MP4/H.264 fixes the "file not supported" error nine times out of ten.
• You're uploading to social. YouTube, Instagram, TikTok, X/Twitter, Facebook, LinkedIn, and Reddit all list MP4 with H.264 + AAC as the preferred upload format. Other containers get re-encoded server-side, which slows publishing and can degrade quality.
• You need a smaller file. A 1080p AVCHD.mts clip from a camcorder often weighs 200-300 MB per minute at 24 Mbps. Re-encoded to H.264 MP4 at CRF 23 it typically shrinks to 30-80 MB per minute with no visible difference.
• You're embedding on a website. The HTML5 <video> baseline that works in every browser without polyfills is H.264 MP4 + AAC. Modern stacks may also ship a WebM/VP9 or AV1 source, but MP4 is the required fallback.
• You're editing in a program that hates exotic codecs. Premiere, Final Cut, DaVinci Resolve, iMovie, and CapCut all import MP4 without third-party codec packs. MKV, RM/RMVB, and older DivX/XviD AVI often need conversion first.
• You want a single archive format. Replacing a folder full of MOV/MKV/WMV/FLV with MP4 makes the library searchable on any device and removes the codec roulette years later.

Supported Input Formats by Source

See dedicated guides for MOV to MP4, MKV to MP4, WebM to MP4, AVI to MP4, HEVC to MP4, MTS to MP4, VOB to MP4, and AVCHD to MP4.

MP4 Codec Compatibility Cheat Sheet

Verified against caniuse.com support tables. "Hardware decode" means the device's GPU/SoC has to accept the codec — software fallback exists in most desktop browsers but drains battery and may stutter at 4K.

Bottom line: ship H.264 unless you have a specific reason. H.265 saves ~30-50% file size at equal quality but loses Firefox on older Windows and most pre-2017 TVs. AV1 saves ~30% over H.265 but is still gated by hardware decoders on phones and older laptops.

MP4 vs WebM vs MKV — When to Use Each

Use MP4 for anything you'll send to another person or upload. Use WebM for your own website's <video> tag where bandwidth matters. Use MKV only as a working archive — convert to MP4 before sharing.

Frequently Asked Questions

How do I convert a video to MP4?

Upload your video (MOV, MKV, WebM, AVI and 30+ more), keep H.264 as the output codec to preserve quality — or pick H.265 for smaller files — then click Convert. Processing runs on our servers, and you download a universally-playable MP4 in seconds. No watermark, no sign-up.

Which input formats can I convert to MP4 here?

Thirty-six in total. The full list: 3G2, 3GP, 3GPP, ASF, AV1, AVCHD, AVI, CAF, CAVS, DIVX, DV, DVR, F4V, FLV, HEVC, M2TS, M2V, M4V, MJPEG, MKV, MOV, MP4, MPEG, MPEG2, MPG, MTS, MXF, OGV, RM, RMVB, SWF, TS, VOB, WEBM, WMV, WTV, XVID. If your file extension isn't there, check whether it's actually one of these in disguise — many "weird" extensions are renamed AVI or MPEG2 containers.

Should I pick H.264 or H.265 (HEVC) as the output codec?

Pick H.264 unless you have a specific reason. H.265/HEVC produces ~30-50% smaller files at the same visual quality, but it still has decode gaps: Firefox only enabled HEVC by default in version 137 (2025), Chrome 107+ requires a hardware HEVC decoder, and TVs/projectors older than ~2017 don't play it. H.264 plays everywhere with zero exceptions. If your goal is "send to anyone, play on anything," stick with the default.

What's the difference between CRF, CBR, and VBR?

CRF (Constant Rate Factor) targets a quality level and lets the file size vary — best for archival and "looks good no matter the content." Typical values: 18 = near-lossless, 23 = web default, 28 = small. CBR (Constant Bitrate) locks the data rate per second — required for some streaming protocols and old satellite/IPTV pipelines. VBR (Variable Bitrate) targets an average bitrate but allocates more to complex scenes — best balance for most uploads. For most people uploading to social, CRF 21-23 or VBR around 5-8 Mbps for 1080p hits the sweet spot.

Will converting to MP4 lose quality?

It's a re-encode, so technically yes — but at default settings the loss is imperceptible. Going from a 24 Mbps MTS camcorder file to H.264 CRF 21 MP4 is essentially invisible side-by-side. The exception is if you re-encode an already-compressed file multiple times (generation loss). If you're starting from an original camera file, one conversion to MP4 is the right move; just don't keep re-converting the result.

Why is my MP4 still huge after conversion?

Three likely causes. First, you may have kept Very High Quality on a long 4K clip — try CRF 23 or scale the resolution to 1080p. Second, you may be encoding a static screen recording with high bitrate — switch to CRF 26-28 for screen content. Third, audio at 320 kbps stereo on a one-hour video adds ~144 MB on its own — drop to 128 kbps AAC if voice-only. The Specific file size preset will pick parameters to hit a target cap automatically.

Does this work for very large videos (multi-GB)?

The practical limit is upload size and connection speed — files are processed on xconvert's servers and deleted automatically after a few hours. For very large files (4K sources over ~5–10 GB), consider trimming to a Time Range first, or splitting into segments with Trim MP4 after a quick re-mux. For everyday phone/camera clips up to a few GB, it works without issue.

Can I just change the file extension from.mkv or.mov to.mp4?

No — that breaks the file. MKV and MP4 use entirely different container structures; renaming .mkv to .mp4 makes the file unreadable. MOV and MP4 share a common ancestor (ISO Base Media File Format) and a renamed MOV often plays, but it isn't reliable across editors. Always re-mux or re-encode through a converter for predictable results.

What audio codec does the output MP4 use?

AAC (Advanced Audio Coding) by default — the codec every MP4-aware device plays. Most modern browsers and devices also accept MP3 in MP4 and AC-3 in MP4, but AAC is the safest cross-platform choice. If you only need the audio track, see video to MP3 instead.

Will subtitles, multiple audio tracks, or chapters survive?

Partially. MP4 supports one primary audio track and embedded subtitles via tx3g, but it doesn't carry MKV-style unlimited tracks, chapters, attached fonts, or HDR10+ metadata cleanly. If your source is an MKV movie with five subtitle languages and director commentary, expect the MP4 to keep one audio + one subtitle stream. For full retention, keep the MKV as the master and produce an MP4 only as the playback copy.

Is the converted MP4 watermarked or limited?

No. Output is clean H.264 MP4 with no watermark, no sign-up wall, no file count cap, no duration limit beyond what your browser can hold in memory. files are processed on our servers and deleted automatically after a few hours and aren't stored on a server after you download.