Is this WEBM to MP4 converter really free?

Yes. Up to 5 files at a time, no signup, no catch. The free tier adds a small watermark to image output — Pro ($9.99/mo or $49/yr) removes it, raises the file size limit to 500 MB, and unlocks unlimited batch conversion.

Are my files uploaded to a server?

No — and you can verify it yourself. Open DevTools → Network tab, then convert a file. You'll see zero upload requests. Everything runs right in your browser. We never see your files.

How long does conversion take?

Usually 1–3 seconds for a typical file. The very first conversion on a fresh page load may take 5–20 seconds while the converter engine loads — after that it's instant. Your CPU does all the work locally.

What is the file size limit?

Free: up to 10 MB per file, 5 files per batch. Pro: up to 500 MB per file, unlimited batch. If you're working with large videos or RAW photos, Pro is built for that.

Can I batch convert multiple WEBM files at once?

Yes — drop multiple files at once (or Ctrl/Cmd+click to select them) and they all convert in parallel. Free accounts handle up to 5 files per batch; Pro has no limit.

How large can my video files be?

Free accounts support files up to 10 MB — enough for short clips and GIFs. Pro raises that to 500 MB, which covers most 1080p videos. For files over 1 GB, a native app like HandBrake will be faster.

Will the video lose quality during conversion?

When only the container changes (e.g., MKV → MP4 where both use H.264), there's zero quality loss — it's a lossless rewrap. When the codec changes, we encode at CRF 23, which is near-transparent for most content.

How private is this converter?

Completely private — by design, not policy. There is no upload endpoint. Files are processed right inside your browser tab and disappear the moment you close it. We collect only anonymous page-view counts; your file content is never seen or stored.

WebM to MP4 Converter — Free, Fast, No Upload

How to convert WEBM to MP4 online

1
Drop your WEBM file
Drag and drop your WebM Video Format file onto the converter, or click to browse your files. You can select up to 5 at once. Nothing leaves your device — conversion happens right here in the browser.
2
Hit Convert — it happens locally
Click Convert and watch it go. There's no upload, no server queue, no waiting. The converter runs WebM Video Format → MPEG-4 Part 14 entirely in your browser tab. Most files finish in 1–3 seconds.
3
Download your MP4
Your MPEG-4 Part 14 file is ready. Click Download, or grab a ZIP if you converted a batch. Close the tab and everything disappears — no copies kept anywhere.

WEBM vs MP4: format overview

WEBM

WebM Video Format

Google (On2 Technologies) · 2010

Compression: lossy
Transparency: No

✓ Royalty-free codec (VP8/VP9/AV1)
✓ Excellent web streaming support
✗ Not supported on iOS/Safari natively

MP4

MPEG-4 Part 14

Moving Picture Experts Group · 2001

Compression: lossy
Transparency: No

✓ Universal compatibility across all platforms
✓ Excellent compression with H.264/H.265

WEBM magic bytes: 1A 45 DF A3

MP4 magic bytes: 00 00 00 xx 66 74 79 70

Why convert WEBM to MP4?

WebM is what you get when you record your screen in Chrome, use Loom, capture video through the browser's MediaRecorder API, or export from OBS with certain settings. It is a web-native format — Chrome, Firefox, and Edge all handle it — but it falls apart everywhere else. Safari does not support WebM. iPhones and iPads cannot play it. AirDrop a WebM to your phone and it will not open. Upload it to an iPhone's camera roll and nothing happens. Smart TVs, Roku sticks, Fire TV, and most standalone media players reject it entirely.

MP4 with H.264 encoding is what every downstream tool expects. You can upload H.264 MP4 to YouTube, Vimeo, Twitter, LinkedIn, Instagram, and TikTok without format errors. You can import it into Premiere Pro, Final Cut Pro, and DaVinci Resolve directly on the timeline. You can AirPlay it, cast it to a Chromecast, or open it in QuickTime on a Mac. For screen recordings that you want to share in a meeting, embed in a presentation, or post anywhere outside a browser, MP4 is the required handoff format.

WebM typically uses VP8 or VP9 video encoding. Converting to MP4 re-encodes the video to H.264, which is a different codec — not a lossless remux. A high-quality encode at CRF 18-23 (H.264 scale) will be visually identical to the source for screen recordings, which contain high-contrast text and flat UI elements. File sizes are comparable or slightly smaller. The one scenario to watch: if the WebM came from a VP9 encode at very high quality, re-encoding to H.264 at default settings can soften fine text at small font sizes — bump the quality setting up if text legibility matters.

Quality & file size: WEBM to MP4

Typical file sizes: WEBM 50–200 MB → MP4 100–300 MB.

Both WEBM and MP4 use lossy compression. We transcode at high quality settings (equivalent to MP4's recommended web quality) to minimize generational loss.

Color depth: WEBM supports standard color, MP4 supports standard color.

Transparency: WEBM does not support transparency. MP4 does not support transparency — transparent areas become solid white.

Frequently asked questions

Privacy: how FormatDrop handles your files

Your WEBM files are converted 100% inside your browser. They are never uploaded to our servers, never stored, and never seen by anyone other than you. This isn't a privacy policy claim — it's an architectural guarantee: our server has no endpoint that receives file bytes.