Penglab Tools

Tools Directory

All utilities run client-side. No data leaves your browser.

JSON Formatter

Format, validate, and inspect JSON payloads directly in the browser without sending data to a server.

XML Formatter

Format, validate, and minify XML documents directly in the browser without uploading data to a server.

Unix Timestamp

Convert epoch timestamps to readable dates and turn human-readable dates back into Unix seconds or milliseconds.

Base64

Quickly encode text to Base64 or decode Base64 strings back into readable content in the browser.

JWT Decoder

Decode JWT header and payload segments in the browser so you can inspect claims without sending tokens to a server.

Diff Checker

Compare two text blocks with line-level and word-level highlighting to review edits, prompts, docs, or config changes.

Multiline to Oneline

Flatten multiline CLI snippets, shell continuations, and markdown-fenced command blocks into a single copy-ready line in the browser.

QR Code

Generate QR codes from URLs or plain text instantly so you can share links, test flows, or hand off data between devices.

Age Calculator

Calculate exact age from a birth date on today or any custom reference date, including years, months, days, total days lived, and time until the next birthday.

D-Day Calculator

Calculate D-day countdowns or elapsed days between a target date and a reference date, including D-10, D-Day, and D+3 style results.

Unit Converter

Convert temperature, length, and weight units such as Celsius to Fahrenheit, meters to feet, and kilograms to pounds in one browser-based tool.

Loan Calculator

Estimate monthly payments for mortgages, car loans, amortizing loans, and interest-only loans with total repayment and total interest figures.

BMI Calculator

Calculate body mass index from height and weight, then view the BMI category instantly.

Percentage

Calculate percentages, reverse percentages, and percentage changes in one browser-based calculator.

Word & Character

Count words, characters, characters without spaces, lines, paragraphs, and estimated reading time from pasted text.

Days Between

Calculate the number of days, weeks, and months between two dates.

Base Converter

Convert whole numbers between decimal, binary, and hexadecimal formats instantly in the browser.

Hex to RGB

Convert HEX color codes to RGB values instantly for design, UI, and frontend work.

Password Generator

Generate strong random passwords with configurable length, symbols, numbers, and mixed case options.

URL Encode

Encode query values and URL fragments safely, or decode percent-encoded strings back into readable text in the browser.

UUID Generator

Generate RFC 4122 version 4 UUIDs in the browser for mock data, IDs, tests, and request correlation.

snake ↔ camel

Convert identifiers between snake_case and camelCase for code, configs, APIs, and database fields.

Text to Slug

Convert titles and free-form text into lowercase URL slugs for posts, docs, routes, and filenames.

Case Converter

Convert text to lowercase or uppercase instantly for cleanup, formatting, and quick copy edits.

Unique Lines

Remove repeated lines from multiline text while preserving the first occurrence of each entry.

Sort Lines

Sort multiline text alphabetically with numeric-aware ordering to organize copied lists quickly.

Time Zone Converter

Convert a date and time between common global time zones such as UTC, New York, London, Seoul, and Tokyo.

Instant Browser Utilities

Privacy First

No server round-trips. Your data stays in the browser.

Zero Setup

No accounts required. Open a tool and start working.