Is my video private when I compress it online?

Yes. Zolkit's Video Compressor processes your video entirely inside your browser using WebAssembly. Your file is never uploaded to a server. The video engine (~30 MB) is downloaded once and cached locally — after that, compression works completely offline.

How do I compress a video to fit Discord's 25 MB limit?

Enable the 'Limit output file size' toggle, click '25 MB', and set resolution to 720p. Zolkit will automatically calculate the correct video bitrate for your file's duration to hit the target size. For a 10-minute video, this typically yields 280–350 kbps video, which looks acceptable in Discord chat. For longer videos, consider 480p to stay within the limit.

Will compressing a video reduce its quality?

All lossy compression reduces quality to some degree. The High Quality mode (CRF 18) is nearly indistinguishable from the original for most footage. Balanced (CRF 23) — the default — reduces file size by 30–50% with minor quality loss that most viewers won't notice. Smaller File (CRF 28) gives the most compression but introduces visible artifacts on fast-moving content.

How do I compress an iPhone video (MOV file)?

iPhone videos are typically HEVC-encoded MOV files, often 4K at 60fps, which can be 1–4 GB for a few minutes of footage. Upload the MOV file directly — Zolkit reads it natively and outputs a compressed H.264 MP4. Set resolution to 720p and quality to Balanced for a good size-to-quality ratio. A 1 GB iPhone video typically compresses to 80–200 MB at 720p Balanced.

Is there a file size limit?

Zolkit does not enforce a file size cap. The practical limit is your device's available RAM — video compression requires loading the file into memory. Most modern computers handle files up to 1–2 GB without issues. For very large files (4K, 60fps), close other browser tabs to free memory before processing.

What video formats are supported?

You can upload MP4, MOV, AVI, MKV, WebM, WMV, M4V, 3GP, FLV, and most other common video formats. The output is always an H.264-encoded MP4 file, which plays on every device and platform without additional software.

Video Compressor

Reduce video file size in your browser — choose quality, resolution, and target size. No upload, no account, completely private.

Drop your video here

or click to browse

MP4, MOV, AVI, MKV, WebM, WMV supported · up to 2 GB

Compression Settings

Quality

Resolution

Audio

Limit output file size

Browse Use Cases

Discord Video Compressor Compress iPhone Video Online Compress MP4 Online Free

Free Online Video Compressor — Reduce Video File Size in Your Browser

Zolkit's Video Compressor uses FFmpeg WebAssembly to compress video files entirely in your browser. Upload MP4, MOV, AVI, MKV, or WebM files and reduce their size by 30–70% without sending your footage to any server. Choose between High Quality, Balanced, and Smaller File modes, pick a target resolution from 360p to 1080p, and set a target file size (for example, 25 MB for Discord Free). All processing happens locally on your device — your videos never leave your browser.

100% Private

Your video never leaves your device. All compression runs entirely in WebAssembly inside the browser tab — no server, no cloud storage.

30–70% Smaller

H.264 re-encoding with CRF quality control typically reduces file size by 30–70% depending on the source material and quality setting.

Advanced Controls

Three quality presets, five resolution options, four audio bitrate settings, and a target file size mode — all visible and adjustable upfront.

FFmpeg-Powered

Uses the same FFmpeg H.264 encoder trusted by professional video editors, compiled to WebAssembly for native-speed performance in the browser.

Free, No Account

No subscription, no sign-up, no watermark. Zolkit's Video Compressor is completely free with no usage limits beyond your device's memory.

Resolution Control

Downscale to 720p, 480p, or 360p to dramatically reduce file size. Lower resolution is the single most effective way to shrink video for sharing.

How to Compress a Video File Online

1
Upload your video — drag it onto the page or click to browse. Supports MP4, MOV, AVI, MKV, WebM, and WMV up to 2 GB.
2
Set compression options: choose quality (High / Balanced / Smaller File), target resolution, audio bitrate, and optionally enable a target file size limit (e.g. 25 MB for Discord).
3
Click 'Compress Video', wait for processing, then preview the size reduction and download the compressed MP4.