J2K Converter

J2K conversion that keeps your files private. reaConverter runs offline on your PC with full batch processing.

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Convert J2K on your PC

For quick and effortless J2K file handling on your PC, reaConverter offers powerful conversion tools with batch processing. Best of all, it works entirely offline — ensuring your sensitive data never leaves your computer.

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Do more with your images

Converting J2K images for use in a workflow? Touch up, transform, apply editing and effects to your images during conversion.

Our range of editing options includes such image processing actions as Resize, Rotate, Crop, Color Replace, Watermarks and more. Adjust actions include RGB, HLS, HSV, Brightness and Contrast. Auto-processing options are also available, such as auto-rotate and auto-crop.

Image editing tools

User Reviews

Average User Rating:
Last updated on November 27, 2025

"For cross-platform compatibility, JPEG remains the gold standard. reaConverter’s precision conversions ensure perfect results every time, whether for presentations, websites, or client deliverables."

Paul Baker

Happy User

"Exactly what I needed! Simple, fast, and no bloat. I use reaConverter Lite to resize and convert batches of images for documents. The presets make it super easy, and everything works smoothly."

Mark Jones

Happy User

"After 200+ conversions on my budget laptop (i3-1115G4/4GB RAM/Win11), reaConverter outperforms heavyweight tools. Zero crashes, low CPU usage during batch processing, and no internet dependency - exactly what professionals need."

Walter Morgan

Satisfied Customer

"This program is incredibly simple and user-friendly, even beginners can use it with ease. It supports batch processing, works offline, and runs smoothly on my aging Acer Aspire laptop. Best of all, the output quality is outstanding!"

Kevin Harris

Happy User

"reaConverter's automation tools have completely changed how I manage my projects. I often work with large batches of illustrations and used to spend hours converting and organizing them. Now, with Watch Folders, I just set the rules once and everything is handled automatically, exactly how I need it. This is pro-level automation made simple."

Chloe M.

Freelance Illustrator

"I use the online converter — it’s quick and hassle-free!"

Jian Wong

Happy Online User

J2K images: Frequently Asked Questions

Can reaConverter open J2K files?

reaConverter fully supports the J2K image format – open, edit, and export J2K files to any other popular file format with ease.

How do I change J2K to another format?

reaConverter is a user-friendly tool for converting J2K files. Once installed on your computer, it allows you to convert all your .j2k files at once with just a few clicks. You can even convert j2k images directly from Windows Explorer using the right-click menu — fast and convenient.

Can I convert J2K online?

If you only want to convert a few J2K images, you are welcome to try our free online J2K converter.

How can I turn J2K files on my computer to another format?

The best way to convert J2K images on your PC is to get 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 J2K.

How can I automate J2K files conversion?

reaConverter supports all the essential automation features, such as right-click сonversion and Watch Folders, for the most efficient automated file conversion in any software of its kind.

Can I convert J2K files using scripts or the command-line interface?

reaConverter provides full access to all its features from the Windows command-line shell, including the command-line j2k converter.

What else can I do with reaConverter?

Change format settings Change DPI Copy metadata (EXIF, IPTC)Convert DICOM files Change photo size