Skip to content
RUEN

Compress video online

Make a video smaller to send it in a messenger or by email, and compare the quality before and after with a slider. Compression runs on your device — the file is not uploaded anywhere.

How it works

  1. Choose a video or drop it into the frame below.
  2. Pick a preset — “Quality”, “Balanced” or “Smallest” — and a resolution; you can drop the audio.
  3. Press “Compress video”, compare the result with the slider and download the MP4.

Formats and limits

FormatsMP4, MOV, WebM, MKV → MP4
Sourceup to 200 MB and 30 minutes
Presets“Quality”, “Balanced”, “Smallest”
Resolutionoriginal or up to 2160p, 1440p, 1080p, 720p, 480p
Audiokeep or remove

Your file stays with you

The video is not uploaded to lac.pics or anywhere else: your browser processes it, on your device. No sign-up needed. You need an account only to save the result to lacuna and send a link: then the file goes to “Uploads” in your account.

Questions

Is the video uploaded to a server?

The video is processed in this tab, on your device: the FFmpeg engine (WebAssembly) is downloaded from lac.pics with the first job — about 30 MB — and then runs locally. The file is not sent anywhere. It reaches lacuna only if you press “Save to lacuna” and sign in.

How much smaller will the file be?

It depends on the video. The frame size after compression is shown in advance, and the result — “−N %” — above the comparison slider. If the file did not get smaller, the page says so and keeps the original.

Which one: “Quality”, “Balanced” or “Smallest”?

“Quality” keeps fine detail better, “Balanced” suits everyday sharing, “Smallest” compresses the most but the loss of detail shows more. A lower resolution also cuts the size noticeably.

Why does compression take a while?

The browser compresses a long video on the graphics card when it can, otherwise on one processor core. Keep the tab open while it works. The lacuna app for Windows compresses faster.

All tools
Compress video online — no server upload · lacuna