Convert G3 to FITS

G3 to FITS conversion that keeps your files private. reaConverter runs offline on your computer with full batch processing support.

reaConverter transforms G3 files to FITS quickly and reliably. Drag in folders, set your options, click Convert, done. No cloud accounts, no file uploads, no complicated setup. Just install and start converting.

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G3 to FITS
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How to Convert Multiple G3 Files to FITS?

1. Download and Install reaConverter

reaConverter is a standalone Windows app — download, install, and start converting G3 files in under two minutes.

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Install reaConverter

2. Load your G3 files

Add your G3 files to reaConverter. Whether it's a handful or an entire archive, the batch engine processes them efficiently.

Browse for files, drag them in, or add entire folders at once. reaConverter queues everything automatically.

Load your G3 files into reaConverter

3. Select FITS as output format

Pick FITS as the output format. Set the destination folder and optionally configure resolution, quality, or file naming.

Select FITS as output format

4. Start G3 to FITS conversion

Start the conversion with one click. reaConverter handles everything and notifies you when it's done.

Start Conversion

When the batch finishes, your FITS files are ready in the destination folder you chose earlier.

G3 to FITS Converter

reaConverter offers the fastest, simplest solution for converting your G3 files into FITS in seconds - all files processed on your PC for maximum privacy and speed.

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Do more with your files

Converting G3 files for use in a workflow? reaConverter offers many ways to process files, so you can customize them according to your requirements.

Our range of editing options includes auto-processing options such as auto-rotate, auto-crop, watermarking and more. Change Color Space, copy Metadata, set DPI, manage ICC Profile, control Bit Depth.

Conversion features
Image editing

User Reviews

Average User Rating:
Last updated on January 17, 2026
"reaConverter makes FITS conversion incredibly easy. We batch convert astronomical images to standard formats for presentations and analysis, all automated through the command-line. It’s fast, reliable, and handles large datasets without issues."
Laura N.
Laura N.
Astrophysics Research Assistant
"Essential for our astroimaging pipeline! reaConverter perfectly handles FITS files from our research telescope, preserving all WCS coordinates and photometric data during batch conversion to TIFF. Now we process 100+ deep-sky exposures nightly without losing critical metadata for our exoplanet studies!"
Joseph Wilson
Joseph Wilson
Satisfied Customer
"Finally an app that actually opens my weird files! Saves me from format frustration daily."
Kyle Brooks
Kyle Brooks
Happy User
"This converter delivers exceptionally quick format conversions with reliable results every time."
Brian White
Brian White
Happy User
"Security was our top concern when evaluating file conversion tools. reaConverter’s offline mode and role-based access controls let us lock it down for sensitive environments. No unexpected network calls or bloat — just clean, fast conversions. Even passed our pen-testing scans without a hitch."
Marcus White
Marcus White
Healthcare IT
"The step-by-step video makes conversion foolproof. I'd recommend this to my grandma - it's that well-explained!"
DeShawn M. Thompson
DeShawn M. Thompson
Happy User

G3 to FITS Conversion: FAQ

What are G3 files?

A G3 file most likely contains the digital image of a document that was either sent or received by fax. Such files use a type of compression called "Group 3", meant to efficiently minimise file size by compressing the white space which generally predominates in faxed documents. G3 files were mostly used during the fax machine era and are currently considered rare and obsolete.

What are FITS files?

The FITS (Flexible Image Transport System) format is a standard format used particularly for storing, transferring and processing scientific images from fields such as astronomy. FITS was first launched as an open standard in the early 1980s and has gone through several subsequent upgrades. FITS files contain not just images, but also data related to photometry and spatial calibration, and information about the origin of the image. Similar formats include FIT and FTS.

Can reaConverter convert G3 to FITS?

Yes! reaConverter instantly converts .g3 to .fits with perfect quality preservation. With its batch processing feature, you can convert multiple files at once in just a few clicks. You can even convert images directly from Windows Explorer using the right-click menu — fast and convenient.

Can I convert G3 to FITS online?

If you only need to convert a few G3 files to FITS format, feel free to try our free online free online G3 to FITS converter — perfect for small batches with no installation needed!

How can I turn G3 files into FITS on my computer?

The best way to change G3s to FITSs on your PC is to install a quality piece of software, such as reaConverter. This software is extremely efficient in managing a wide range of batch files conversions, including conversion from G3 to FITS.

How can I automate G3 to FITS files conversion?

reaConverter supports all the most useful automation features such as right-click сonversion and Watch Folders for the most efficient automated files conversion in any software of this type.

Is there a way to convert G3 files to FITS using the command prompt?

reaConverter provides full access to all its features via Windows command line, including a high-performance command-line g3 to fits converter for batch processing.

What else can I do with reaConverter?

Convert vector imagesConvert picture color spaceConvert CAD formatsSet image bit depthChange format settings

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