How to Convert Video to MP4 on Windows and Mac: 2026 Guide

MP4 is the most compatible video format for sharing between Windows, Mac, iPhone, Android, and smart TVs. If a video won’t play on your device or upload to a platform, converting it to MP4 usually fixes the problem. We tested five conversion tools on Windows 11 and macOS Sonoma and found HandBrake handles every format without watermarks or file size limits.

#How to Convert Video to MP4 With HandBrake on Windows and Mac

HandBrake is the most reliable free option. It handles MKV, AVI, MOV, WMV, FLV, WebM, and every other format we tested. We processed a 3 GB MKV file on both Windows 11 and macOS Sonoma without any errors or quality loss.

1. Download HandBrake from handbrake.fr.
2. Open HandBrake and drag your video file into the window.
3. In the Output Settings, confirm the container is set to MP4.
4. Select a preset: Fast 1080p30 works well for most files.
5. Click the folder icon next to Save As to choose an output location.
6. Click Start Encode.

HandBrake shows a progress bar with estimated time remaining. A 1 GB file takes about 5-8 minutes on a modern laptop. The output file plays on every device and platform we tested, including older Windows Media Player and Samsung smart TVs. According to HandBrake’s official documentation, the encoder supports hardware acceleration on Nvidia, AMD, and Apple Silicon GPUs, which can cut conversion time by 50-70% compared to software-only encoding on supported machines.

#Converting Video to MP4 With VLC Media Player

Yes, VLC has a built-in converter that works for one-off conversions. It’s slower than HandBrake but useful if you already have VLC installed. We converted a 2 GB MKV to MP4 using VLC 3.0.20 on Windows 11 in about 12 minutes.

1. Open VLC and go to Media > Convert / Save (Ctrl+R on Windows, File > Convert / Stream on Mac).
2. Click Add and select your video file.
3. Click Convert / Save at the bottom.
4. Under Profile, select Video - H.264 + MP3 (MP4).
5. Set a destination file with an .mp4 extension.
6. Click Start.

VLC doesn’t support batch conversion through its GUI. For multiple files or anything over 2 GB, use HandBrake or FFmpeg instead. VLC’s documentation confirms that it supports over 400 codec and container combinations natively without installing separate decoder packs.

#FFmpeg: The Fastest Method for Batch Video Conversion

FFmpeg converts entire folders of videos in one terminal command. In our testing, FFmpeg converted a 2 GB MKV to MP4 using stream copy (no re-encoding) in under 20 seconds, compared to 8 minutes with HandBrake’s full encode.

Install FFmpeg from ffmpeg.org, then use these commands:

Convert a single file:

ffmpeg -i input.avi -codec:v libx264 -crf 23 output.mp4

Fast container swap (no quality loss, works when both use H.264):

ffmpeg -i input.mkv -codec copy output.mp4

Batch convert all AVI files in a folder (Windows):

for %f in (*.avi) do ffmpeg -i "%f" -codec:v libx264 -crf 23 "%~nf.mp4"

Batch convert on Mac/Linux:

for f in *.avi; do ffmpeg -i "$f" -codec:v libx264 -crf 23 "${f%.avi}.mp4"; done

The -crf 23 flag controls quality (18=excellent, 28=smaller file, 23=default balance). Lower numbers produce higher quality and larger files.

#Which Online Converter Works Best for MP4 Conversion?

Online converters work without installing anything. We tested CloudConvert and FreeConvert with a 500 MB MKV file:

CloudConvert was the fastest in our testing and produced clean output without watermarks. Go to cloudconvert.com, click Select File, choose your video, set output to MP4, and click Convert.

Limitations of online converters:

• Most cap at 1 GB on the free tier
• Upload time is the main bottleneck on slower connections
• Not suitable for sensitive or private videos

For files over 1 GB or batches of videos, HandBrake or FFmpeg on your local machine is significantly faster.

#MP4 Quality Settings for Every Use Case

The correct settings depend on your use case. In our testing across 20+ test encodes, these settings produced the best balance:

For sharing via WhatsApp, email, or social media: Use 720p resolution with H.264 at CRF 28. A 5-minute clip comes out around 100-150 MB. Most platforms re-compress uploads anyway, so high bitrate is wasted.

For archiving at full quality: Use original resolution with H.264 at CRF 18-20. File size increases significantly, but quality is visually lossless.

For device compatibility: H.264 plays on every device made in the last 15 years. H.265 (HEVC) produces 40% smaller files at the same quality but requires a device from 2018 or later for smooth playback. Use H.264 when in doubt.

For YouTube uploads: Google’s YouTube upload documentation states that YouTube recommends H.264 video with AAC audio at 128 kbps in an MP4 container for the best compatibility with their processing pipeline.

#Why Is My Converted MP4 File Larger Than the Original?

This happens when converting from a more compressed format (like FLV or WMV) to MP4 with a higher bitrate than the source. The encoder uses more data per second than the original file did.

Fix: check the source file’s bitrate in VLC (go to Tools > Media Information > Statistics tab) and set your HandBrake or FFmpeg bitrate to match or slightly lower. This single adjustment can reduce output size by 50-60% compared to default settings that many converters set unnecessarily high.

Converting from H.265 to H.264 also produces larger files, since H.264 requires more data for equivalent quality.

#Bottom Line

HandBrake is the right tool for most users on Windows and Mac. It’s free, handles every format, and produces clean MP4 output with no file size limits. Use FFmpeg for batch conversions or when you need precise control from the command line. CloudConvert works for quick online conversions when your file is under 1 GB. See our guide on converting specific video formats to MP4 for format-specific tips, our MTS to MP4 guide for camcorder footage, or our guide on extracting images from video if you need still frames. For compression after conversion, see our guide on compressing video for email and how to compress MP4 files without losing quality.

#Frequently Asked Questions