# Probably Useful App

> Free browser\-based calculators, generators and utilities for work, websites, money and everyday tasks—plus clear guides that explain the results\.

Generated by Yoast SEO v28.6, this is an llms.txt file, meant for consumption by LLMs.

## Pages
- [Tools](https://probablyuseful.app/tools/)
- [Terms of Use](https://probablyuseful.app/terms/): The basic terms that apply when you use Probably Useful tools, guides, and website content\.
- [Privacy Policy](https://probablyuseful.app/privacy-policy/): How Probably Useful handles website usage data, contact forms, cookies, analytics, advertising, and browser\-based tools\.
- [How We Build Our Tools](https://probablyuseful.app/how-we-build-tools/): The principles we use when designing, testing, and maintaining Probably Useful tools\.
- [Editorial Policy](https://probablyuseful.app/editorial-policy/): How Probably Useful researches, writes, reviews, updates, and corrects its guides\.

## Posts
- [JSON vs Base64 vs URL Encoding: What Each Does](https://probablyuseful.app/data-encoding-formats-guide/): Learn why JSON structures data, Base64 represents bytes as text, and URL encoding makes data safe inside URL components\.
- [How Word Counts and Reading Time Estimates Work](https://probablyuseful.app/word-count-reading-time/): Learn why word and character counts can differ between tools and how reading\-time estimates are calculated\.
- [How to Read, Format and Fix JSON](https://probablyuseful.app/how-to-read-fix-json/): Learn the structure of JSON, the syntax errors that break parsing, and a practical process for debugging malformed data\.
- [How to Make a Clear, Professional Invoice](https://probablyuseful.app/how-to-make-a-simple-invoice/): A practical invoice checklist covering identity, invoice numbers, line items, taxes, due dates, payment instructions, and record keeping\.
- [How to Create Strong, Manageable Passwords](https://probablyuseful.app/how-to-create-strong-passwords/): Use long, unique passwords, a password manager, and multi\-factor authentication without relying on predictable complexity tricks\.

## Tools
- [Word \& Character Counter](https://probablyuseful.app/tools/word-character-counter/): Count words, characters, sentences, paragraphs, and estimated reading time instantly as you type or paste text\.
- [UUID Generator](https://probablyuseful.app/tools/uuid-generator/): Generate one or many UUID v4\-style identifiers in your browser for development, testing, APIs, and distributed records\.
- [UTM Builder](https://probablyuseful.app/tools/utm-builder/): Build a campaign URL with source, medium, campaign, term, and content UTM parameters using a consistent naming structure\.
- [URL Slug Generator](https://probablyuseful.app/tools/url-slug-generator/): Turn a title or phrase into a clean lowercase URL slug with readable separators and an optional length limit\.
- [URL Encoder \& Decoder](https://probablyuseful.app/tools/url-encoder-decoder/): Percent\-encode text for use inside URL components or decode percent\-encoded values back into readable text\.

## Categories
- [Developer Basics](https://probablyuseful.app/category/developer-basics/)
- [Business Math](https://probablyuseful.app/category/business-math/)
- [Web Basics](https://probablyuseful.app/category/web-basics/)
- [Everyday Math](https://probablyuseful.app/category/everyday-math/)
- [Marketing](https://probablyuseful.app/category/marketing/)

## Tool Categories
- [Finance](https://probablyuseful.app/tools/category/finance/)
- [Developer](https://probablyuseful.app/tools/category/developer/)
- [Web](https://probablyuseful.app/tools/category/web/)
- [Business](https://probablyuseful.app/tools/category/business/)
- [Text](https://probablyuseful.app/tools/category/text/)

## Optional
- [Sitemap index](https://probablyuseful.app/sitemap_index.xml)