Password Generator
Generate strong random passwords with custom character sets.
Open toolFree online tools for developers and everyday tasks
Corexo brings together 30 fast, reliable utilities in one place — formatters, encoders, generators, calculators and converters. Everything runs right in your browser. No sign-up, nothing to install, and results appear instantly as you type.
UUID Generator
Create one or many UUID v4 values for app development.
Open toolJSON Formatter
Validate, prettify, and minify JSON instantly.
Open toolAge Calculator
Calculate exact age from a date of birth in years, months, and days.
Open toolPercentage Calculator
Solve common percentage operations in seconds.
Open toolUnix Timestamp Converter
Convert Unix timestamps to readable dates and back again.
Open toolHTML Entity Encoder
Encode and decode HTML special characters like ampersands and angle brackets.
Open toolIP Address Lookup
Show your current public IP address and copy it quickly.
Open toolText Formatter
Transform and clean text for docs, code, and content.
Open toolRandom Number Generator
Generate truly random numbers in any range with optional duplicate exclusion.
Open toolWord Counter
Count words, characters, sentences, paragraphs, and reading time instantly.
Open toolQR Code Generator
Create free QR codes for URLs or text. Download as SVG. No account needed.
Open toolColor Picker
Pick any color and convert between HEX, RGB, and HSL formats instantly.
Open toolBase64 Encoder / Decoder
Encode text or files to Base64 and decode Base64 strings back to plain text.
Open toolLorem Ipsum Generator
Generate placeholder lorem ipsum text for mockups, wireframes, and design layouts.
Open toolURL Encoder / Decoder
Encode special characters for safe URL use or decode percent-encoded strings.
Open toolRegex Tester
Test regular expressions against a string and see matches highlighted in real time.
Open toolDiff Checker
Compare two texts line by line and see added, removed, and unchanged lines.
Open toolUsername Generator
Generate unique, memorable usernames for games, apps, and social accounts.
Open toolJWT Decoder
Decode JSON Web Tokens and inspect header, payload, and expiry claims.
Open toolHash Generator
Generate SHA-1, SHA-256, SHA-384, or SHA-512 hashes from any text.
Open toolMarkdown Preview
Write Markdown and see the rendered HTML preview side by side, instantly.
Open toolSlug Generator
Convert any title or phrase into a clean URL-safe slug with accent normalization.
Open toolZeit-Rechner
Add, subtract, or find the difference between two time durations in HH:MM:SS format.
Open toolBMI Calculator
Calculate body mass index with metric or imperial units.
Open toolLoan Calculator
Estimate monthly payments, total interest, and an amortization schedule.
Open toolCountdown Timer
Create a live countdown to any event date and time.
Open toolColor Converter
Convert colors between HEX, RGB, HSL, and HSV with a live preview.
Open toolRoman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers.
Open toolMoon Phases
Live lunar phase, illumination, and the next New, Quarter, and Full Moon dates.
Open toolWhat is Corexo?
Corexo is a free collection of small, single-purpose web tools for people who work with text, code and numbers every day. Instead of installing a desktop app or trusting a random site for a one-off task, you open the tool you need, paste your data, and get the result immediately. Each tool does one thing well and loads in under a second, so it is just as comfortable to reach for during a coding session as it is on your phone.
Most tools run entirely in your browser. When you format JSON, generate a password, or calculate a BMI value, the work happens on your own device — the data you type is not sent to a server to be processed. That makes Corexo fast, private, and usable even on a flaky connection.
What you can do here
- Developer utilities — format and validate JSON, encode or decode Base64 and URLs, generate UUIDs, hash text, decode JWTs, and test regular expressions.
- Text tools — count words and characters, change letter case, build URL slugs, generate Lorem Ipsum, compare two texts, and preview Markdown.
- Calculators — work out percentages, body mass index, loan repayments, and exact age between two dates.
- Generators — create strong passwords, QR codes, random numbers, and ready-to-use usernames.
- Converters — convert colors between HEX, RGB and HSL, Roman numerals, and Unix timestamps to readable dates.
Why people use Corexo
The tools are free and need no account. There is no paywall, no trial, and nothing to download — you can bookmark the exact tool you use most and jump straight to it. The layout is the same everywhere, so once you have used one tool you already know how the next one works. Every page is mobile-friendly, which means the same calculator or generator works on a laptop, a tablet, or a phone on the move.
Frequently asked questions
Are the tools really free?
Yes. Every tool on Corexo is free to use with no account and no usage limit. The site is supported by unobtrusive ads, not by charging you.
Do you store the data I enter?
For the great majority of tools, no. The calculation or conversion runs in your browser, so the text or numbers you type are processed on your device and are not uploaded to us.
Do I need to create an account?
No. There is no login, no sign-up form and no email required. Open a tool and start using it right away.
Do the tools work on mobile?
Yes. Every tool is responsive and built to work on phones and tablets as well as on desktop browsers.