Convert JSON to CALS Online
Convert JSON images to CALS format free, fast, and privately in your browser.
Drag & drop files, or browse
Up to 20 images at once
How to convert JSON to CALS
Upload your files
Drag & drop or browse up to 20 JSON files at once.
Browser converts locally
Files convert to CALS in your browser - nothing is uploaded anywhere.
Download results
Save files individually or download everything as a ZIP bundle.
Why use this converter
100% Private - Nothing Uploaded
Your JSON files never leave your device. All conversion happens locally inside your browser using WebAssembly. Zero server contact.
Batch + ZIP Download
Convert up to 20 JSON files to CALS at once and download them all as a single ZIP archive in one click.
Lossless Output Quality
CALS is a lossless format - every pixel from your JSON file is preserved exactly with no compression artifacts.
Instant Conversion
Your JSON files convert to CALS in seconds using WebAssembly - no waiting, no queues.
Frequently asked questions
4 questionsUpload your JSON files by dragging them into the drop zone or clicking Browse. Select up to 20 files at once, then click Convert. Your files are processed locally in your browser and ready to download in seconds - no account or internet connection needed after the page loads.