How to Batch Convert Files in 2026 (Free, Local, Cross-Platform)

One-off file conversion is easy. Batch conversion is where most tools fall apart. The cleanest free converters max out at one file at a time. The bulk-friendly tools are usually paid, ad-heavy, or built around a specific format. And the command-line option (FFmpeg, ImageMagick) requires writing a shell loop you have to remember every time.

This guide covers the three best ways to batch convert files in 2026: a desktop app for the easy path, online tools when you cannot install software, and the command line for power users with thousands of files. The right choice depends on the size of your batch and how often you will repeat it.

Watch: Batch conversion in How to Convert

Here is what batch conversion looks like in How to Convert. Drop a folder, pick a target format, hit convert. Everything happens locally.

Method 1: How to Convert Desktop App (Easiest, Local, Cross-Platform)

How to Convert handles batch conversion for video, audio, image, and document formats from the same app. Drop a folder onto the window, pick the target format, and the app converts every supported file in one pass. Output goes into a sibling folder so the originals are never overwritten.

Steps

• Open the How to Convert desktop app.
• Drag a folder onto the window (or click Add and pick the folder).
• Pick the target format. The app applies it to every file.
• Click Convert. Watch the progress per file.

Since the app runs locally, batch conversion of large folders is fast and your files never leave your computer. This matters for sensitive data (recordings, scans, photos) where uploading to a web tool is risky or against policy.

Method 2: Command Line (Best for Power Users and Scripts)

For scripted or recurring batch jobs, the command line is unbeatable. Three workhorses cover most needs:

FFmpeg for video and audio

# Batch convert all MP4 files in a folder to MP3
for f in *.mp4; do ffmpeg -i "$f" -vn -c:a libmp3lame -b:a 192k "${f%.mp4}.mp3"; done

# Batch convert all MKV to MP4 (lossless remux when possible)
for f in *.mkv; do ffmpeg -i "$f" -c copy "${f%.mkv}.mp4"; done

ImageMagick for images

# Batch convert all PNG files in a folder to JPG
magick mogrify -format jpg *.png

# Batch resize all JPG files to 1920px wide
magick mogrify -resize 1920x *.jpg

Pandoc for documents

# Batch convert all Markdown files to PDF
for f in *.md; do pandoc "$f" -o "${f%.md}.pdf"; done

Wrap any of these in a shell function or alias for repeated use. The command line scales to thousands of files without slowing down.

Method 3: GUI Tools per Format Type

If you want a free GUI tool focused on a specific format, these are the best free options:

• Video: Shutter Encoder (FFmpeg GUI, batch friendly).
• Audio: fre:ac (open source batch audio converter).
• Images: XnConvert (batch image converter with chained operations).
• Documents: LibreOffice (command line: libreoffice --headless --convert-to pdf *.docx).

Method 4: Online Batch Tools (When You Cannot Install Software)

Online converters work for batch jobs but with limits: file size caps, time-per-day quotas, and uploads required. CloudConvert handles batch through its API for paid plans. FreeConvert has the most generous file size limit (1 GB free). For sensitive files, prefer a local tool.

How to Avoid the Common Batch Pitfalls

• Test on one file first. Make sure the output settings are right before you commit a 500-file batch.
• Output to a different folder. Never overwrite originals until you have verified the output.
• Watch disk space. Converting 100 GB of MOV files to MP4 still needs 100 GB of free space.
• Mind file naming. If filenames have special characters or spaces, quote them in shell loops.
• For huge jobs, run overnight. A few thousand HD video re-encodes can take hours.

Frequently Asked Questions

What is the fastest way to batch convert video files?

FFmpeg with stream copy is the fastest when the codecs are already compatible (for example, MKV to MP4 with H.264 video). Use -c copy to avoid re-encoding. For re-encoding batches, hardware acceleration via -c:v h264_videotoolbox (Mac) or -c:v h264_nvenc (NVIDIA) makes a huge difference.

Can I batch convert files of different formats at once?

Yes. The How to Convert desktop app accepts mixed input formats and applies the chosen output format to each. Most command-line approaches require a separate command per input format, so a folder with mixed formats may need a couple of shell loops.

How do I batch convert images?

ImageMagick is the standard: magick mogrify -format jpg *.png converts every PNG in the current folder to JPG in place. For a GUI alternative, XnConvert handles batch image conversion with chained operations like resize and watermark.

What about batch converting Word docs to PDF?

LibreOffice has a headless mode: libreoffice --headless --convert-to pdf *.docx. This converts every .docx in the current folder to PDF without opening the GUI. Faster than going through the GUI for large batches.

Final Thoughts

For most people, the right batch tool is the How to Convert desktop app: drop a folder, pick a format, done. For power users running recurring jobs, the command line scales to any size. For the in-between case where you want a free GUI focused on one format, Shutter Encoder, fre:ac, and XnConvert are the strongest free options. Pick the tool based on how often you will repeat the job, not just the size of the first batch.