Developer Calculators
Free developer tools for every need. All calculations happen in your browser. No signup, no tracking.
Base64 Encoder & Decoder: Encode/Decode Online
Encode text or data to Base64, or decode Base64 strings back to readable text. Supports UTF-8 text, URLs, and binary data encoding. 100% client-side.
CSS Beautifier / Formatter (Free Online)
Format minified or messy CSS into clean, readable, consistently indented code. The perfect companion to our CSS Minifier.
CSS Box Shadow Generator with Live Preview
Build layered CSS box shadows with visual sliders for offset, blur, spread, color, and inset. Live preview plus copyable CSS output.
CSS Minifier & Beautifier: Compress CSS Online
Minify CSS by removing whitespace, comments, and redundant code. Or beautify minified CSS for readability. Free online CSS compressor tool.
CSS Specificity Calculator: Score Any Selector
Compare CSS selectors and get the specificity triple (a, b, c) with a per-part breakdown and a clear winner. Handles IDs, classes, :not(). Free.
Chmod Calculator: Octal Permissions
Calculate Linux chmod permissions: click the 9 permission bits or pick a preset to get the octal number, symbolic form, and shell command. Free.
Color Blindness Simulator: Test Your Designs
Pick a color and preview how it looks with protanopia, deuteranopia, and tritanopia. Includes WCAG contrast ratios for accessible design. Free.
Cron Expression Generator and Plain-English Explainer
Build cron schedules visually, or paste any expression to get a plain-English explanation plus the next 10 run times. Free, no signup.
Download Time Calculator: File Size and Speed
Estimate how long any file takes to download. Enter file size and connection speed, use one-touch presets for 5G, fiber, cable, DSL, 4G. Free.
Epoch Converter with Time Zones
Turn a Unix timestamp into dates across time zones (UTC, New York, London, Karachi, local) or convert a date back to epoch. Shows ISO 8601. Free.
Free Password Strength Meter (Private)
Check password strength with live scoring, estimated crack time, and specific suggestions. Runs 100% in your browser, nothing sent or stored. Free.
Free QR Code Generator (No Signup, No Expiry)
Create QR codes for URLs, WiFi, vCards and text. Generated 100% on your device, never expire, no tracking redirects. Free, no signup.
Free URL Parser: Break Down Any URL
Parse any URL into its parts: protocol, host, port, path, query parameters (decoded), and fragment. Free online URL parser, no signup.
HTML Entity Encoder & Decoder: Escape HTML Online
Encode HTML special characters to entities or decode entities back to characters. Prevents XSS and display issues. Named and numeric entities. Free.
HTML Minifier: Compress HTML Code Online
Minify HTML online: remove comments, collapse whitespace, and shrink file size. Protects pre, textarea, script, and style content. Free, no signup.
HTML to Markdown Converter (Free Online)
Convert rich HTML into clean Markdown. Paste from web pages or editors; get normalized headings, lists, links, and code blocks.
Hex to RGB Converter: Color Code Converter Online
Convert hex color codes to RGB, HSL, and HSB values instantly. Pick any color and get all formats. Color palette generator included.
JSON Validator & Formatter: Pretty Print JSON Online
Validate, format, and pretty-print JSON instantly. Detect errors with exact line numbers, minify, expand, and copy formatted JSON. 100% client-side.
JSON to CSV Converter (Nested Data Supported)
Convert JSON to CSV or Excel-ready files with nested object flattening, delimiter choice and live preview. Free, no signup.
JSON to TypeScript Interface Generator
Paste JSON and generate TypeScript interfaces automatically. Optional fields, readonly modifiers, and export styles included.
JWT Decoder: Decode JSON Web Tokens Online (Private)
Decode JWT tokens instantly in your browser. View header, payload claims and expiry dates. Your token never leaves your device. Free, no signup.
Markdown to HTML Converter (Live Preview)
Paste Markdown and get clean, semantic HTML instantly with live side-by-side preview, plus copy and download buttons. Free, no signup.
Open Graph Preview Tool + Meta Tag Generator
Preview how your link looks on Facebook, X, LinkedIn, and Slack. Get copy-ready OG and Twitter Card meta tags. Free, no signup.
PPI Calculator (Screen Pixel Density)
Calculate PPI from resolution and screen size, plus megapixels, aspect ratio, and print sizes at 300, 150, and 72 DPI. Free, no signup.
PX to REM Converter (and REM to PX)
Convert px to rem and rem to px instantly. Set your base font size, see the em equivalent, and browse a live table of common pixel values. Free.
Regex Tester: Regular Expression Tester Online
Test, debug, and explain regular expressions in real time. Highlights matches, shows groups, supports all JS regex flags. Free online regex tool.
SQL Formatter & Beautifier: Format SQL Online
Format and beautify SQL queries for readability. Supports SELECT, INSERT, UPDATE, DELETE, CREATE TABLE and common SQL clauses. Free online SQL formatter.
Subnet Calculator: IP Ranges, Masks, and CIDR
Enter an IP and CIDR to get the network address, broadcast address, subnet mask, wildcard mask, usable hosts, and IP range. Free, no signup.
URL Encoder & Decoder: Percent-Encode URLs Online
Encode special characters in URLs to percent-encoding, or decode %XX sequences back to text. Essential tool for building and debugging web URLs.
WCAG Contrast Checker (AA/AAA)
Check color contrast ratios against WCAG 2.1. Get AA/AAA pass-fail badges for normal and large text, plus one-click fixes.
Webhook Signature Verifier (HMAC-SHA256)
Paste a payload, enter your secret, and check whether the HMAC-SHA256 signature matches. Works like Stripe verification. 100% in-browser. Free.
XML Formatter, Validator & Minifier
Pretty-print, minify, and validate XML documents. Get precise error messages pointing at the exact line of malformed markup.
YAML to JSON Converter (Bidirectional)
Convert YAML to JSON and JSON to YAML bidirectionally, with inline validation errors for broken configs. Free, no signup.