A 10-minute 4K clip can be several gigabytes — too big for email, slow to upload, and annoying for viewers. Video compression shrinks files by trading a little quality for a lot of size. This guide explains the levers that matter (bitrate, resolution, codec and container), what settings suit common use cases, and how to compress video online without uploading it.
The Four Levers of Video Size
- Bitrate: data per second (Mbps). The single biggest lever — halving bitrate roughly halves file size.
- Resolution: pixel dimensions. Dropping 4K→1080p reduces pixels by 75%.
- Codec: how frames are encoded (H.264, H.265/HEVC, VP9, AV1). Newer codecs get better quality at the same bitrate.
- Container: the wrapper (MP4, WebM, MKV). MP4 with H.264 is the most compatible choice.
Starting Points by Use Case
| Use case | Resolution | Bitrate | Format |
|---|---|---|---|
| Email / chat | 720p | 1–2 Mbps | MP4 (H.264) |
| Social upload | 1080p | 3–6 Mbps | MP4 (H.264) |
| Web/streaming | 1080p | 2–4 Mbps | MP4 or WebM |
| Archive / highest quality | Source | 10+ Mbps | MP4 (H.265/AV1 if supported) |
How to Compress Video Online
- Open the tool: go to the video compressor.
- Upload the video: MP4, WebM and more; the file stays on your device.
- Pick a resolution: keep the source or scale down to 1080p/720p.
- Set the bitrate: start from the table above and preview the quality.
- Choose a preset: quick presets cover the common scenarios above.
- Export: the compressed file plays right in the browser for a final check.
Tip: for the same visible quality, newer codecs (HEVC/AV1) need lower bitrates — but older devices may not play them. When in doubt, use H.264 in an MP4; it plays everywhere.
Frequently Asked Questions
What bitrate should I use for 1080p?
For general sharing, 3–6 Mbps for H.264 at 1080p30 is a good range; lower for simple content (slides, screen recordings), higher for busy motion.
Why is my compressed video still large?
Usually the bitrate is still high, or the resolution wasn't reduced. Check the output bitrate — lowering it is the most effective next step.
Which format is most compatible?
MP4 with H.264 (AVC) plays in essentially every browser, phone and editor. Use WebM (VP9/AV1) only when you control the playback environment.
Is my video uploaded when I compress it?
No. The video compressor transcodes locally in your browser — your video never leaves your device.
References
- Video compression primer — Google web.dev: https://web.dev/media/
- H.264 vs HEVC vs AV1 — Cloudflare Learning Center: https://www.cloudflare.com/learning/video/what-is-video-compression/