1Drop your MKV videos into the box above, or pick them from your device — there is nothing to install and no account to create.
2Choose how much to compress with the setting shown for this file type: a quality level for images, a bitrate for audio, or a target size or quality level for video.
3Start the job and let the workers re-pack the file; your original is never modified in place.
4Compare the new size against the original, then download the compressed MKV file.
Compress MKV FAQ
Does the format of my file change how much I can save?
+
Very much so. MKV imposes no codec restrictions and carries unlimited audio, subtitle and chapter tracks, which is why rips use it and TVs often refuse it. That determines both the headroom available and whether the saving costs you anything in fidelity.
Is there anything specific to MKV I should know before compressing?
+
Yes — MKV places no restriction on what is inside it, so an edit has to carry every audio, subtitle and chapter track across rather than assuming one of each. It is worth knowing before you overwrite an original you might need again.
How does Compress MKV actually make the file smaller?
+
Concretely, the picture is re-encoded through x264 or x265 at the CRF you set, optionally scaled down first; CRF 23 is visually transparent on most footage and each step of about six roughly halves the file again. Nothing about it depends on you installing software: the job runs server-side and hands back a finished file.
How much smaller will my file get?
+
That is decided by the content, not by the tool. Photographic detail and film grain resist compression; flat colour, text and silence collapse. A realistic expectation is a large reduction on anything with big uniform regions and a modest one on a busy photograph or a high-motion clip.
What can I upload to Compress MKV?
+
MP4, MOV, MKV, WebM, AVI, WMV, FLV, 3GP, M4V, MPEG and MPG. The container and codec are probed before anything runs, so a mixed batch is handled correctly per file rather than assumed to be uniform.
Is there a file size limit on Compress MKV?
+
Yes: free accounts process video up to 40 MB per file, by far the most generous cap on the site; ffmpeg with x264, x265 and libvpx does the work, which is the same toolchain behind most desktop video software. Video is the one family where the cap is high enough that upload time, not the limit, is what you will actually notice.
Why would a modern-format site run Compress MKV?
+
WEBP.to is built around the modern replacement for both of the old defaults: one format that does lossy, lossless, alpha and animation, and reliably lands smaller than the JPEG or PNG it came from. People arrive here having decided the old defaults are costing them bandwidth, and that decision immediately raises the rest: what size, what quality, what happens to the transparency. Compress MKV is on the same upload and the same account so those questions get answered in one place.
Once Compress MKV has run, what is worth doing next?
+
The converter on this site moves images to and from WebP, PNG, JPG and AVIF, which is where you decide whether a smaller file is worth losing the older browsers. Doing it in that order matters: pick the pixels first and the container afterwards, because the container is the cheap decision and the pixels are the expensive one.
Do the sibling sites run something different?
+
The engines are identical — same libraries, same workers, same caps. What is different is the opinion attached, and the opinion here rests on a property of the format this site is named after: the same .webp extension can hold a lossy VP8 frame, a lossless one, or an animation, so the sensible processing path is decided per file rather than per extension.
What happens to my file, and is an account required?
+
No account is needed. Uploads and results are kept for about 24 hours, which leaves time to download the result, and are then deleted automatically; nobody reads, lists or indexes them. Several files in one job need a paid plan.
