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Convert Multiple Videos at Once

Drop in a folder of mixed-format videos. Pick one destination format. Download the whole batch.

  • Convert dozens of videos in a single queue
  • Mixed inputs (MP4, MOV, MKV, WebM) handled per file
  • Local processing, no upload, no per-file server timeout
  • Compress and resize in the same pass
  • Download files individually or as a ZIP

Overview

The single-file converter pattern stops being useful at file number two. Drag, wait for upload, wait for conversion, download, switch tab, drag again, multiplied by twenty clips from a shoot or a folder of screen recordings, the click overhead alone takes longer than the encoding ever does.

This tool treats batch as the default. Drop in 5, 20, or 100 files, set the output format and quality once, and the queue processes each file locally on your device. Throughput depends on your device, browser, source files, and chosen settings. On a modern laptop, common batches can process quickly because there is no upload step or server round trip.

Inputs can be mixed: a queue of MOVs from your phone, MKVs from OBS, and WebMs from the browser screen recorder all convert to the same destination in one pass.

Technical notes

Throughput

On recent laptops, moderate-sized batches of common formats can often finish quickly. Skipping uploads removes a meaningful chunk of the per-file wall time compared with server-side converters.

Worked example

Compression can reduce total batch size substantially, especially when lowering quality or output width, though exact savings vary a lot by content.

Mixed input batches

Each file in the queue is decoded and re-encoded independently, so MOV, MKV, MP4, and WebM inputs can sit side by side and all output to the same target format.

Good to know

Browser memory caps the batch

Multi-hundred-file batches can exhaust browser memory on lower-end devices. If a long queue starts to slow down, split it into smaller groups.

Hardware encode availability varies

Throughput depends on whether the browser and device expose hardware acceleration for the selected codec. A software path may be slower when available; unsupported codec configurations fail.

Sources: W3C: WebCodecs specification · Reviewed 2026-10-12

Tab sleep pauses the queue

If your laptop sleeps or the browser throttles a backgrounded tab, the queue pauses and resumes when the tab is active again. Disable system sleep for very long batches.

How to batch convert many videos at once

Batch convert many videos at once in your browser without uploading any files.

01

Add your videos

Drag and drop your video files into the converter, or click to pick them.

02

Choose your settings

Pick the output format, quality, optional width, and whether to remove audio.

03

Start the batch

Click Convert files. Each file is processed locally on your device.

04

Download

Download files individually, or grab the whole batch as a ZIP.

Frequently Asked Questions

Are my files uploaded anywhere?

No. The whole batch runs in your browser via WebCodecs. Files stay on your device. There is no upload endpoint for video.

How many files can I queue at once?

There is no hard cap. Many modern laptops can handle fairly large queues of typical 1080p files, but practical limits depend on memory, storage, browser behavior, and file complexity.

Can I mix input formats in one batch?

Yes. Each file is converted to the chosen output format independently, so MOV, MP4, MKV, and WebM inputs can all sit in the same queue.

What if my laptop sleeps mid-batch?

The queue pauses while the tab is suspended and resumes when the tab is active again. For very long batches, disable system sleep while the conversion is running.

Which browsers does this work in?

Conversion requires WebCodecs video encoding and decoding, but each browser and device supports a different codec subset. MP4, MOV, and MKV output use H.264 video with AAC audio; Firefox and desktop Linux browsers do not natively encode AAC. Safari 16.4 added video WebCodecs, while Safari 26 added audio encoding and decoding. WebM output uses VP9 with Opus and may work where AAC output does not. For the widest support, use a recent desktop Chrome or Edge release, or Safari 26+. The converter still validates the actual source and output codec configuration when a job starts.

Sources: MDN: WebCodecs API · MDN: WebCodecs codec selection · WebKit: WebCodecs video support in Safari 16.4 · WebKit: WebCodecs audio support in Safari 26 · Mediabunny: supported formats and codecs · Reviewed 2026-10-12

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