Blog & Guides
Tutorials and tips for using our free online tools.
How to Compress Images for Email Attachments
Tested results at 50%, 70%, and 90% quality — exact file sizes, what breaks, and the sweet spot for email.
How to Convert PNG to JPG Without Losing Visible Quality
Real conversion tests showing file size reduction, quality loss thresholds, and when PNG-to-JPG makes sense.
How to Check if Your Password Is Actually Strong
Five passwords tested from 'password123' to random passphrases — which ones survive and why length beats complexity.
How to Format JSON Data So It Is Actually Readable
Pretty-printing, syntax highlighting, and catching errors in raw API output — tested with real JSON.
How to Count Words and Characters for Essays, Emails, and SEO
What counts as a word, reading time estimates, and how PDF copy-paste can inflate your character count.
How to Split a PDF into Separate Files
Extract specific pages from a large PDF — tested with a 24-page document at various page ranges.
How to Convert JPG to WebP for Faster Websites
Five JPG photos converted to WebP with exact size comparisons and browser compatibility details.
How to Generate UUIDs for Database Keys, APIs, and Testing
UUID v4 explained, batch generation tested, and when to use UUIDs vs auto-increment IDs.
How to Encode and Decode Base64 Strings Online
What Base64 actually does, real encoding examples, and why it is not encryption.
How to Rotate a PDF Page That Is Sideways or Upside Down
Fixing scanned documents with mixed orientations — tested with 6 pages at 90°, 180°, and 270° rotations.
How to Convert Celsius to Fahrenheit (and Back) Without Errors
Formulas, quick reference table, and tested conversions including the -40° crossover point.
How to Extract Specific Pages from a PDF Document
Pick exactly the pages you need from a larger PDF — non-contiguous selection tested.
How to Convert Text Between Uppercase, Lowercase, Title Case, and Sentence Case
Four case types tested with the same input, plus when to use each case style.
How to Validate JSON and Find Syntax Errors Instantly
Four common JSON errors tested — missing commas, trailing commas, single quotes, and empty input.
How to Calculate Percentages, Discounts, and Percentage Changes
Three types of percentage calculations with real-world examples and the most common mistake.
How to Calculate the Exact Number of Days Between Two Dates
Leap year handling, year-boundary crossing, and tested date pairs with verified results.
How to Encode and Decode URLs for Web Development and APIs
Percent-encoding explained with real examples, common character codes, and the double-encoding trap.
How to Sort Text Lines Alphabetically or in Reverse Order
Sorting tested with names, numbered lists, and mixed case — plus the ASCII ordering gotcha.
How to Calculate the Right Tip Amount at Restaurants
Tipping etiquette by country, exact calculations tested, and the pre-tax vs post-tax tip debate.
How to Compress an Image Without Losing Quality
Learn the best techniques to reduce image file size — from JPG and PNG to WebP — while maintaining visual quality.
How to Reduce PDF File Size
Simple steps to compress PDF documents for easier sharing, faster uploads, and email attachment limits.
JPG vs WebP: Which Should You Use?
A comparison of JPG and WebP image formats — compression, quality, browser support, and when to use each.
How to Merge PDF Files
Combine multiple PDF documents into a single file in seconds — no software installation needed.
How to Resize Images Online Without Losing Quality
Resize images for web, social media, or email with this free tool — tested with real photos.
How to Calculate US Sales Tax in Any State
All 50 states plus D.C. covered — learn state rates, local taxes, and which states have no sales tax.
Calculate Your Exact Age in Years, Months and Days
Handles leap years, shows total days lived, and counts down to your next birthday.
Reverse Text Online — Flip Words, Characters, and Lines
Reverse text, words, or lines instantly. Choose character reversal, word reversal, or line order reversal.
How to Clean Up Text — Remove Extra Spaces and Line Breaks
Remove extra spaces, line breaks, and special characters from text instantly. Free browser-based text cleaner with instant results.
How to Encode and Decode HTML Entities Online
Convert <, >, &, and quotes to HTML entities and back — tested with XSS payloads. Free browser-based encoder with instant results.
How to Make AI Content Plagiarism-Free (Free Tool)
Make AI-written content plagiarism-free with a free humanizer. Two modes tested — rewrite AI text or generate fresh original writing.
Pounds to Kilograms Conversion Table (lbs to kg)
Pounds to kilograms table from 1 to 200 lbs, the exact factor, worked examples and a reverse kg to lbs chart.
Miles to Kilometers Conversion Table (mi to km)
Miles to kilometres table from 1 to 100 miles, race distances, the exact formula and a reverse km to mi chart.
BMI Chart by Height - Weight Ranges for 5'0 to 6'4
Healthy, overweight and obese weight ranges by height in pounds and kilograms, with the reverse BMI formula.
BMI Percentile Chart for Kids and Teens by Age
Calculate BMI for a child or teenager and read the CDC BMI-for-age percentile bands, with worked examples in kg/cm and lb/in.
QR Code Guide — Make, Scan and Print QR Codes
What a QR code stores, how to make one for a link, WiFi, WhatsApp or a contact card, print sizes that scan, PNG vs SVG, and why free QR codes stop working.