✅ Last updated: August 12, 2026
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JSON Formatter & Validator
Format and validate JSON online
🔒Base64 Encoder Decoder
Encode and decode Base64 strings
🔗URL Encoder Decoder
Encode and decode URL strings
#️⃣Hash Generator
MD5, SHA-1, SHA-256, SHA-512
🆔UUID Generator
Random UUID v4 generator
🔍Regex Tester
Test regular expressions live
🪙JWT Decoder
Decode JSON web tokens
🎨Color Converter
HEX, RGB, HSL, CMYK conversion
📝Markdown Editor
Live markdown preview
🔀Diff Checker
Compare two texts or files
📊JSON to CSV Converter
Convert JSON arrays to CSV
📋CSV to JSON Converter
Convert CSV to JSON format
🌐IP Address Lookup
Find your IP and location
🛡️Password Strength Checker
Entropy and crack time estimate
🖼️Image to Base64
Encode images for HTML/CSS
Frequently Asked Questions
Yes, 100% free. No subscription, no credits, no watermark, no file size limit. Every tool on Calcus is free forever.
Completely. All processing happens in your browser. No files or data are sent to any server. Your inputs never leave your device.
Most tools work offline after the first load since they run entirely in JavaScript. Calculator tools, converters, and text tools all work without internet.