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Practical guides for real tasks — written by the people building the tools on this site.
Showing 2,416–2,436 of 2,462 articles
🏋️ Health & Fitness
How to Calculate Your Running Pace
Calculate running pace per km and per mile, plus speed in km/h and mph, from any distance and time, to plan a race or check a training split.
💻 Developer Tools
How to Catch YAML Syntax Errors Before They Break Your Build
Validate YAML syntax with a live JSON preview and exact line and column error locations, before a bad indent breaks your CI pipeline or config.
✍️ Text & Writing
How to Check Character Limits Before You Post
Count characters and words live as you type, then check your text against Twitter/X, Instagram, and SMS limits before you hit post. Free and runs in your browser.
🔒 Security & Privacy
How to Check if a Credit Card Number Is Valid
Learn how the Luhn algorithm catches mistyped card numbers, why network detection matters, and how to validate a card number without sending it anywhere.
🔀 Data & CSV
Check If a Parquet File Is Valid
Check whether a .parquet file has a valid header and footer and see its file size, before you load it into a data pipeline. Free and runs in your browser.
📅 Date & Time
Check If a Year Is a Leap Year
Check whether any year is a leap year, with a plain explanation of the rule and a list of the next five leap years ahead. Free and instant, no math required.
🔍 SEO & Web
How to Check If Your Meta Description Is Too Long
Preview how your title and meta description will look in Google search results and check the exact pixel-width cutoff before you publish, free and in your browser.
🔀 Data & CSV
Convert a Font File Between TTF, OTF & WOFF
Preview a font with your own text and convert it between TTF, OTF, WOFF, and WOFF2, without design software. Free and processed entirely in your browser.
🔀 Data & CSV
Convert an Excel Sheet to CSV Without Excel
Convert an XLSX sheet to CSV without installing Excel, picking your delimiter and previewing the result before you download. Runs in your browser.
🔀 Data & CSV
Convert an HTML Table Into a CSV File
Convert HTML table markup into a CSV file, ready to copy or download, without opening a spreadsheet app or writing a scraper. Free and browser-based.
🔤 Text & Writing
How to Convert Text Case Without Retyping Everything
Switch between UPPERCASE, Title Case, camelCase, and more without manually fixing every letter. What each case style is actually for, and how to convert instantly.
🔀 Data & CSV
Convert XML to JSON Without Writing a Parser
Convert XML into clean JSON live as you type, with attributes, nested elements, and repeated tags handled automatically. Free and runs in your browser.
📅 Date & Time
Count Down the Days Until Your Birthday
See a live, second-by-second countdown to your next birthday showing days, hours, minutes, and seconds remaining. Free and runs right in your browser.
🔒 Security & Privacy
How to Encrypt and Decrypt Text With a Vigenère Cipher
Learn how the Vigenère cipher's keyword-based shifting works and how to encrypt or decrypt text with it for classes, puzzles, or classic cryptography practice.
🔍 SEO & Web
How to Extract Every URL From an XML Sitemap
Pull every URL out of a pasted XML sitemap or sitemap index into a clean list, with a count and text-file download, entirely in your browser.
🎧 Video & Audio
How to Extract MP3 Audio From a Video File
Pull the audio track out of an MP4 or MOV and save it as an MP3 without installing an editor. What actually happens during extraction and how to do it in your browser.
🎲 Generators
How to Find a Gift Idea When You're Stuck
Get a gift idea filtered by interest and budget for any recipient, when you're out of ideas and running out of time before the occasion.
📅 Date & Time
Find the Moon Phase for Any Date
Calculate the moon phase, cycle age, and approximate illumination percentage for any date, past or future, without an astronomy app. Free and instant.
💻 Developer Tools
How to Clean Up Minified or Messy CSS Fast
Reformat minified or messy CSS into clean, consistently indented stylesheets that preserve comments, live as you type, without installing a build tool.
🎲 Generators
How to Generate a Random Excuse for Fun
Get a random, category-filtered excuse for work, school, or social plans, for games, icebreakers, or a laugh — not for actually skipping anything.
🎲 Generators
How to Generate a Secure Random PIN
Create random numeric PINs of any length, in batches, with an optional no-repeated-digits mode, for accounts, devices, and shared codes.