---
title: "MP4 to WebM Converter — Smaller Web Video | Compress Pro"
description: "Convert MP4 videos to WebM right in your browser — typically smaller at the same visual quality, ideal for the web. No uploads, no accounts. Free & private."
canonical: https://compress-pro.com/mp4-to-webm
---

# Convert MP4 to WebM.

> MP4 to WebM in your browser — smaller video, same quality.

Convert MP4 videos to WebM right in your browser — **everything runs on your device, nothing is uploaded**. WebM (VP9) usually lands noticeably smaller than MP4 at the same visual quality, which makes it the go-to format for websites and web apps. The audio track comes along too.

**No uploads · No ads · Free & open source.**

## How it works

1. Drop files anywhere on the page, click to browse, or paste with Ctrl/⌘ + V.
2. Pick a quality or preset — or set an exact target size and let the tool find it.
3. Compress, compare before/after, and download — individually or as a ZIP.

## Smaller video for your own site

VP9 typically lands well under H.264 at the same visual quality, and on a website that difference is paid out on every single view. Background loops, product demos and portfolio reels are the sweet spot — the places where you control the player and every megabyte shows up in load time.

## Keep an MP4 fallback

Apple devices still handle WebM inconsistently, so the safe pattern is to serve WebM first and let Safari fall back to the MP4 you already have. And if a WebM ever needs to travel the other way, [WebM to MP4](https://compress-pro.com/webm-to-mp4) reverses the conversion.

## Frequently asked questions

### Why convert MP4 to WebM?

Smaller files at the same visual quality — VP9 typically beats H.264 by a clear margin, which matters for websites, portfolios and anything users have to download.

### Where does WebM not play?

The Apple ecosystem is the big exception — Safari handles WebM inconsistently and iPhones don’t preview it natively. For web pages and modern browsers it is a first-class citizen.

### What happens to the audio?

It is converted to (or kept as) Opus, WebM’s native audio format — excellent quality at small sizes.

### Is my video uploaded during conversion?

No. Encoding runs on your own hardware from first frame to last — nothing streams to a server, which is also why there is no file-size cap and no queue. Close the tab and every trace of the footage is gone. Want proof? Run one file through, switch your connection off, and run another — it still works.

## Related tools

- [Compress videos](https://compress-pro.com/compress-video)
- [Convert WebM to MP4](https://compress-pro.com/webm-to-mp4)

---

Part of [Compress Pro](https://compress-pro.com/) — every tool page has a markdown twin at `<page url>.md`. Full tool index: [llms.txt](https://compress-pro.com/llms.txt)