Convert MOV to MP4

Pick a QuickTime .mov and get an .mp4 — a lossless container remux when possible, re-encode when needed. Runs in your browser, nothing is uploaded.

Convert MOV to MP4 in your browser

A QuickTime .mov and an .mp4 are the same underlying container format — they usually differ only in the box on the outside. When your MOV already holds the codecs MP4 uses (H.264 or HEVC video with AAC audio, which is what almost every iPhone, DSLR and mirrorless camera records), converting it is just a remux: the video and audio packets are copied straight into an MP4 wrapper with no re-encoding. That's lossless, changes nothing about the picture or sound, and finishes in a fraction of a second.

Everything runs locally with ffmpeg compiled to WebAssembly — your file is never uploaded to a server.

Two modes

Remux (default) — stream-copies with -c copy and writes a web-friendly +faststart MP4. Lossless, near-instant, no quality change. Use this for normal phone and camera clips.
Re-encode to H.264/AAC — for MOVs whose codecs MP4 can't legally hold, the most common being Apple ProRes (from ScreenFlow, Final Cut exports, and pro cameras). Re-encoding always produces a valid MP4; it's slower and lossy, so the quality slider (1–100, default 75) trades size against fidelity.

Worked example

Take a 6-second iPhone clip beach.mov (H.264 video + AAC audio). Leave the mode on Remux and drop the file in. Out comes beach.mp4 with the exact same H.264 video stream and AAC audio stream — identical duration and dimensions, no visible change — ready to attach to an email or upload anywhere that rejects .mov.

If instead you had a ProRes screen recording, Remux would fail with a codec error; switch to Re-encode to H.264/AAC and it converts (re-encoding the picture to H.264).

Limits

Input and output are each capped at 10 MiB — trim or compress longer clips first.
Remux mode requires MP4-legal codecs; if it errors, use Re-encode mode.
Output is always an .mp4 (H.264/HEVC video, AAC audio). To target WebM instead, use the video-transcode tool.

FAQ

Does converting MOV to MP4 lose quality?

In Remux mode, no — it's a lossless container change. The exact H.264/HEVC video and AAC audio streams are copied into the MP4 wrapper untouched, so the result is bit-for-bit the same video, just in a different box. Only Re-encode mode is lossy, because it genuinely re-compresses the picture.

Why is the conversion so fast?

Because in the default Remux mode nothing is re-encoded. Re-encoding video is the expensive part; a remux only rewrites the container metadata and copies the already-compressed packets across, so a short clip converts in well under a second.

My MOV won't remux — it errors. What now?

That means the MOV holds a codec MP4 can't carry — most often Apple ProRes (common in ScreenFlow recordings and Final Cut exports). Switch the mode to Re-encode to H.264/AAC, which always produces a valid MP4. It's slower and lossy, so raise the quality slider if you want to preserve more detail.

What does the quality slider do, and when does it matter?

It only applies in Re-encode mode, where 1–100 maps onto a practical slice of ffmpeg's libx264 CRF scale (higher = better quality and a larger file): 100 is visually lossless (CRF 18), the default 75 is roughly CRF 24, and 1 is small and low quality (CRF 40). In Remux mode it's ignored entirely, because a stream-copy never re-encodes.

Is my video uploaded anywhere?

No. The conversion runs entirely in your browser using ffmpeg compiled to WebAssembly — the file never leaves your device, and the page works offline once it has loaded.

Developer & Automation Access

Run it from the terminal

Same engine as this page, headless — via the gizza CLI:

gizza tool mov-to-mp4 'url=https://example.com/input' 'mode=copy' 'quality=75'

New to the CLI? Get gizza →

Open it by URL

Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:

https://gizza.ai/tools/mov-to-mp4/?url=https://example.com/input&mode=copy&quality=75