§00 WebM Compressor

Compress WebM Online — Free, No Watermark

Shrink browser WebM recordings and web video to an exact size in MB. Keep WebM or export a compatible MP4 — no watermark, nothing to install.

Drag & drop a video here to get started
Guests: up to 250 MB · Free plan: 1 GB · Paid: up to 10 GB
MP4, MOV, MKV, AVI, WebM, WMV, M4V, 3GP, MPEG and more
Compression preset
Target size:MB
Fit to:

Quality mode targets CRF and does not guarantee an exact MB size. Switch to target size or bitrate for a hard limit.

Only use this for very old devices or playback issues (reduces compression ratio).

Estimated cost: — credits
§01 WebM Files

Why WebM files get heavy — and where they stop working

WebM is Google’s open video format for the web. Inside is usually VP8 or VP9 video with Vorbis or Opus audio — excellent for HTML5 players and screen recordings, but not always friendly when you leave the browser. A long WebM capture can run hundreds of megabytes, and some email clients, chat apps and older players still prefer MP4/H.264. Compressing WebM to a smaller file — optionally re-wrapping as MP4 — solves size and compatibility in one step.

§02 Where WebM Hits a Wall

Typical upload limits when sending or posting video

These caps apply to the file you attach — WebM or MP4. Aim a little under the limit so container overhead never pushes you over.

DestinationUpload limitCompress to
Gmail attachment25 MB24 MB
Outlook / work emailOften 20–25 MB19 MB to be safe
Discord (free)20 MB19 MB
Discord Nitro Basic50 MB48 MB
Website / CMS media libraryUsually 2–64 MB (set by the host)5% under the stated limit
Learning portals & formsOften 10–100 MBCheck the form, then leave headroom

Limits checked October 2026. Discord raised its free upload limit from 10 MB to 20 MB in August 2026 — older “8 MB” guides are outdated. Limits checked October 2026. Full breakdown: Discord file size limit.

§03 How It Works

How to compress a WebM file online

No FFmpeg command line, no desktop install — set a size and download. Keep WebM or convert to MP4 in the same pass.

  1. STEP 1

    Upload the WebM

    Drop a WebM export, screen recording or browser capture into the compressor above. MP4, MOV, MKV and AVI work too if your source is not WebM yet.

  2. STEP 2

    Set a target size (or a percentage)

    Type the size you need in MB — 24 for Gmail, 19 for Discord — or pick a preset like “50% smaller”. The tool derives a bitrate from the clip’s length so the result lands close to your target.

  3. STEP 3

    Download WebM or a compatible MP4

    Keep a leaner WebM for the web, or choose MP4/H.264 when the destination is email, chat or an older player. No watermark, nothing burned into the frame.

§04 Bitrate Math

How small can a WebM go before quality drops?

File size ≈ bitrate × duration. Use this as a planning table before you compress.

Video lengthTarget sizeRough total bitrate
15 seconds19 MB~10 Mbps — sharp 1080p is easy
30 seconds19 MB~5 Mbps — clean 1080p
60 seconds24 MB (Gmail)~3.2 Mbps — good 1080p / 720p
2 minutes19 MB~1.3 Mbps — 720p recommended
5 minutes19 MB~0.5 Mbps — 480p or cut a highlight
60 seconds50% smallerHalf the original — usually looks fine

If the picture falls apart, lower resolution before starving the bitrate further. Long screen recordings almost always look better as a short highlight than as a five-minute clip forced under 20 MB.

§05 Compatibility

When to keep WebM — and when to switch to MP4

WebM (VP9/Opus) is great inside a modern browser. The moment a file leaves that environment — email attachment, chat app, older smart TV, some LMS players — MP4 with H.264 and AAC is the safer bet. This tool can produce either.

Keep WebM for the open web

HTML5 <video>, portfolio sites, and Chrome/Firefox playback love a lean VP9 WebM. If the file will live on your own page and size matters, staying in WebM is usually fine.

Convert to MP4 when recipients complain

“It won’t open” almost always means the player lacks VP9/Opus. Re-encoding to H.264 MP4 is the fix — same story as iPhone HEVC MOV on Windows.

Watch the audio track

Opus is modern and efficient; unusual PCM or multi-track audio bloats the file and can break embeds. AAC stereo at 64–128 kbps is plenty for clip audio.

§06 FAQ

WebM compression FAQ

Answers for browser captures and web video that will not send.

How do I compress a WebM file?

Upload the WebM to the compressor on this page, set a target size in MB (or a percentage), and download the result. You can keep WebM or export MP4 — no desktop software required.

What is a WebM file?

WebM is an open media format designed for the web. It typically holds VP8 or VP9 video with Vorbis or Opus audio. Browsers play it natively; many email clients and older apps prefer MP4 instead.

Should I compress WebM or convert it to MP4?

Compress WebM when the file stays on the web and players are modern. Convert to MP4/H.264 when you attach it to email, send it in chat, or the recipient reports it will not open.

Will compressing a WebM lose quality?

Re-encoding always trades some detail for size. At sensible targets — a 30-second clip to 19–24 MB — most people will not notice on a phone or laptop. Extreme squeezes on long high-resolution footage will soften the image.

What size should a video be for email?

Stay under the provider’s attachment cap: Gmail 25 MB, many Outlook and work systems 20–25 MB. Compress to 24 MB or 19 MB so overhead does not push the file over.

Can I compress a WebM without FFmpeg?

Yes. Use the tool on this page in any modern browser. You set the target size and download the file — no command line, no install.

Ship the WebM, not the error

Compress WebM to the size you need — free to start, no watermark, nothing to install.

Compress a WebM nowSee plans & credits