Free · No Upload · Instant

Convert MP4 to FLV Free Online — Best MP4 to FLV Converter 2025

Convert MP4 to FLV online for free. Fast, private MPEG-4 Video to Flash Video converter — no upload, no signup. Works in your browser instantly.

Choose Files

or drag and drop files here

Max file size: 2GB

Your files are processed locally in your browser. Nothing is uploaded to any server.

How to Convert MP4 to FLV

Upload your MP4 file by clicking "Choose Files" or drag and drop it.

Select FLV as the output format.

Click "Convert Now" and download your converted file.

About MP4 Format

Extension: .mp4
Full name: MPEG-4 Video

About FLV Format

Extension: .flv
Full name: Flash Video

Frequently Asked Questions

Is it safe to convert MP4 to FLV online?

Yes! Convert999 processes all files directly in your browser. Your files are never uploaded to any server, ensuring complete privacy and security.

How long does it take to convert MP4 to FLV?

Conversion is nearly instant for most files. Large files may take a few seconds depending on your device's processing power.

Is there a file size limit?

Convert999 supports files up to 2GB. Processing happens locally, so larger files depend on your device's available memory.

Do I need to install any software?

No installation required. Convert999 works entirely in your web browser on any device.

Can I convert MP4 to FLV on my phone?

Yes! Convert999 works on any device with a web browser — iPhone, Android, iPad, or desktop. No app installation required. Simply open the converter, upload your MP4 file, and download the converted FLV file.

Will I lose quality converting MP4 to FLV?

Convert999 uses high-quality conversion algorithms to minimize quality loss. For lossless formats, the conversion is exact. For lossy formats like images and audio, we use optimized settings that balance quality and file size.

Can I batch convert multiple MP4 files to FLV?

Yes, Convert999 supports batch conversion. Select or drag & drop multiple MP4 files and convert them all to FLV format at once. Each file is processed locally in your browser.

What is the difference between MP4 and FLV?

MPEG-4 Video (MP4) and Flash Video (FLV) differ in compression, compatibility, and features. MP4 is optimized for its native use cases, while FLV may offer different advantages. Visit our MP4 vs FLV comparison page for a detailed breakdown.

Why Convert MP4 to FLV?

Advantages

✓Flash Video offers better compatibility with modern applications and workflows
✓Converting is completely free with no file size limits on Convert999
✓Your files never leave your device — 100% private and secure conversion
✓Instant conversion without waiting for server processing

Key Differences

→MP4 (MPEG-4 Video) is optimized for its native use cases
→FLV (Flash Video) may offer different compression or feature set
→Choose based on your target platform, quality needs, and file size requirements

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