FLV to MP4 Converter – Free Online

Video & Audio Converter

Total Estimated Output Size: 0.00 KB

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Video

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Format

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FORMAT

MP4

WEBM

MKV

MOV

FLV

AVI

Selected Files

Add File

Select All

Select Settings

Video

Audio

Format

Resolution

Advanced Settings

FORMAT

MP4

WEBM

MKV

MOV

FLV

AVI

Total Estimated Output Size: 0.00 KB

Convert

How to Convert FLV to MP4 Online

Upload your FLV file

Drag and drop your .flv file onto the page or click to browse. You can select several FLV files at once to batch-convert them.

MP4 is preselected

The output format is already set to MP4, so you can convert immediately. If you need to, adjust the codec, resolution, frame rate or bitrate in the settings panel first.

Convert and download

Click Convert. The MP4 file is processed on your own device; nothing is uploaded to a server. When it finishes, click Download to save it (or Download all to get a batch as a ZIP).

Why Convert FLV to MP4?

Flash is gone, and with it every browser's ability to play FLV. Converting FLV to MP4 rescues old downloads, screencasts and web videos into a format that plays anywhere and uploads to YouTube, Drive or social media.

Most FLV files carry H.264 video with AAC or MP3 audio. The converter decodes the FLV in your browser with FFmpeg and re-encodes it into an MP4 at the resolution and bitrate you choose, so nothing is uploaded and there is no size limit.

Private by design: your FLV file is converted on your own device and never uploaded.
MP4 preselected: the output format is already chosen, so it is a one-click conversion.
Batch friendly: convert several FLV files in one go and download them as a ZIP.
No limits, no watermark: free for files of any size, with nothing stamped on the output.

FLV vs MP4

FLV (Flash Video): FLV (Flash Video) was the streaming format of the Flash era. Modern browsers no longer play it, so FLV files usually need converting before they can be watched or edited. It is best for legacy Flash-era archives.

MP4 (MPEG-4 Part 14): MP4 is the most widely supported video container in the world. It usually carries H.264 or H.265 video with AAC audio, plays on every phone, browser, TV and editing app, and is the safest choice for sharing. It is best for sharing, social media, web playback and mobile devices.

In short: keep FLV when the priority is legacy Flash-era archives, and switch to MP4 when the file is headed for sharing, social media, web playback and mobile devices. Need a different target? The full Video Converter supports every format listed below.

FLV to MP4 FAQ

Do all FLV files convert?

FLV files with H.264, Sorenson Spark (H.263) or VP6 video are all decoded by the in-browser FFmpeg build and re-encoded to H.264 for the MP4.

Will the MP4 keep the original quality?

The video is re-encoded, so keep the original resolution and a bitrate at or above the source to stay visually identical. Lowering either shrinks the file at the cost of some detail.

Is this FLV to MP4 converter free?

Yes. Converting FLV to MP4 on MediaConverter.io is completely free, with no watermark, no sign-up and no daily conversion limit.

Are my FLV files uploaded to a server?

No. The converter runs inside your browser using WebAssembly and WebCodecs, so your .flv file is read and converted on your own device. Nothing is uploaded, which keeps private recordings private and means there is no waiting in an upload queue.

Is there a file size limit for FLV to MP4?

No fixed limit. Because processing happens locally, the practical limit is your computer's memory and patience; multi-gigabyte FLV files convert fine on a desktop browser. Very large files take longer on phones.

Which browsers support the FLV to MP4 converter?

Current versions of Chrome, Edge, Firefox and Safari on desktop all work. Chrome and Edge are fastest because they expose hardware-accelerated WebCodecs decoders.