Convert ACORN to CAL

Convert ACORN to CAL without quality loss. reaConverter gives you full control over resolution, compression, and output settings.

Manual ACORN to CAL conversion wastes hours. reaConverter automates the process — just add files and click Convert. Everything happens offline on your computer — no uploads, no cloud risks.

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How to Convert Multiple ACORN Files to CAL?

1. Download and Install reaConverter

reaConverter installs quickly on any Windows PC. No dependencies, no bloatware — just a clean setup that's ready to use immediately.

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Install reaConverter

2. Load your ACORN files

Open reaConverter and add your ACORN files. You can load individual files, entire folders, or even nested subfolders.

Drop your ACORN files into the window or use File menu to browse and select folders.

Load your ACORN files into reaConverter

3. Select CAL as output format

Choose CAL as the target format. Pick a destination folder or let reaConverter save files alongside the originals.

Select CAL as output format

4. Start ACORN to CAL conversion

Hit Convert and let reaConverter do the work. The progress window shows status for each file in real time.

Start Conversion

After conversion, find your CAL files in the output folder. Click 'Show converted files' to open it directly.

ACORN to CAL Converter

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

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Do more with your files

Converting ACORN 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 25, 2026
"5/5⭐ Finally! Does what it promises - converts AND tweaks images without complicated menus. Perfect for quick jobs."
J. Mitchell
J. Mitchell
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"reaConverter is pure gold! Rock-solid performance with zero crashes. No internet needed—perfect for travel or low-connectivity work. The ultimate offline alternative to sketchy web converters. Plus, the desktop version keeps sensitive files secure since nothing ever gets uploaded to the cloud."
Malik T. Martin
Malik T. Martin
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"I was skeptical at first, but reaConverter exceeded my expectations. The interface is intuitive, and the advanced settings let me tweak outputs perfectly. Plus, the customer support is fantastic!"
Sarah Lane
Sarah Lane
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"This software just works! My old laptop can’t handle Photoshop, but reaConverter flies through conversions without breaking a sweat. Wi-Fi gone? Still strong!"
Robert Williams
Robert Williams
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"Rare software that actually does it all! Converts anything, beautiful interface, and never lets me down. A must-have!"
Henry R.
Henry R.
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"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
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ACORN to CAL Conversion: FAQ

What are ACORN files?

The ACORN file format is associated with Acorn Sprite or RISC OS Sprite and it represents a bitmap image of up to 32 bpp. ACORN images usually store application icons and screenshots, but they can also store multiple images. As the standard file format for storing bitmap images in the RISC OS system, ACORN files are usually found on computers which run this system, such as the Acorn Archimedes. RISC OS was an operating system used in the late 1980s and 1990s, and at the moment ACORN files are considered rare and obsolete.

What are CAL files?

A CAL image file represents a monochrome bitmap image that uses the CALS raster image standard for storing graphics data. This standard was created in the 1980s by the US Department of Defence as a compressed interchangeable image format. CAL and CALS are extensions used for similar purposes.

Can reaConverter convert ACORN to CAL?

Yes! reaConverter instantly converts .acorn to .cal 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 ACORN to CAL online?

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

How can I turn ACORN files into CAL on my computer?

The best way to change ACORNs to CALs 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 ACORN to CAL.

How can I automate ACORN to CAL 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 ACORN files to CAL using the command prompt?

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

What else can I do with reaConverter?

Copy metadata (EXIF, IPTC)Change format settingsChange DPISet manual file dateConvert GIS files

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