Guides & Articles
Practical, plain-English guides to getting more out of the tools — written by the people who build them.
How to Reduce Image Size to KB (20 KB, 50 KB, 200 KB)
A form that says "maximum 200 KB" is not asking you to guess at a quality slider. Here is how to hit the number exactly, why "200 KB" means two different things, and what it costs in pixels.
Images ··8 min read
Crop PDF Pages Individually, Not All at Once
How to crop PDF pages individually rather than applying one crop to the whole document — and why the box you draw lands in the wrong place on some files.
PDF ··8 min read
File Hash Generator: Verify a SHA-256 Checksum
How to verify a downloaded file against the SHA256SUMS file its publisher ships, without copying one hash out of forty by hand.
Developer ··8 min read
How to Add Page Numbers to a PDF (and Why They Go Missing)
Page numbers are easy until the number lands somewhere the reader cannot see. How to number a PDF properly, why "Page 1 of 10" and "Page 1 of 20" are both right, and the cropped-page trap that hides the number on print-ready files.
PDF ··9 min read
JPG to PDF: How to Turn Photos and Scans into One PDF
Converting images to a PDF is a container operation, not a re-compression — a JPEG goes in untouched. How to make one PDF from a folder of photos, which tools actually keep the file on your device, and why your pictures come out sideways.
PDF ··10 min read
How to Remove EXIF Data from a Photo (No Quality Loss)
Every phone photo carries hidden text: where it was taken, when, and on what device. Here is how to see it, how to remove it without damaging the picture, and which apps quietly pass it on.
Images ··9 min read
How to Watermark a PDF (and What a Watermark Does Not Do)
A watermark labels a document; it does not protect it. How to stamp every page of a PDF properly, why the stamp comes out sideways on scans, and when you actually need redaction instead.
PDF ··8 min read
How to Convert HEIC to JPG (Why iPhone Photos Won't Open)
Your iPhone saves photos as HEIC, and almost nothing outside Apple can open them. Here is how to convert them to JPG, and how to stop the problem at the source.
Images ··7 min read
How to Create a QR Code for a Website URL
A URL QR code turns a web address into something people can scan. Here is how to create one and what to put in it.
QR Codes ··7 min read
How to Split PDF Files Into Separate Documents
Need to break a PDF into smaller files? Here is how to split a PDF into separate documents, extract page ranges, and avoid the usual mistakes.
PDF ··7 min read
What Is a CPS Test and How to Test Your Clicking Speed
A CPS test measures how many clicks you can make in one second. Here is what CPS means, how to run a click speed test, and how scores compare.
Games ··7 min read
BMI Calculator — What It Measures and What It Means
A BMI calculator uses height and weight to estimate body mass index. Learn what the numbers mean, how to interpret the result, and when BMI is useful.
Calculator ··6 min read
How to Calculate BMI (Complete Guide)
Learn how to calculate your Body Mass Index (BMI). A practical guide to understanding BMI categories and what they mean for your health.
Calculator ··8 min read
How to Compress Images Without Losing Quality
Learn how to compress images without losing quality. A practical guide to reducing file size while keeping your photos sharp and clear.
Images ··8 min read
How to Remove Image Backgrounds (Complete Guide)
Learn how to remove image backgrounds online. A practical guide to making backgrounds transparent for ecommerce, social media, and design.
Images ··8 min read
How to Encode Images to Base64 (and When to Do It)
Learn how to encode images to Base64. A practical guide to understanding Base64 encoding, when to use it, and the tradeoffs involved.
Images ··7 min read
How to Crop Images for Maximum Impact
Learn how to crop images for maximum impact. A practical guide to composition, aspect ratios, and getting the best result every time.
Images ··8 min read
How to Resize Images for Social Media
Learn how to resize images for Instagram, Facebook, Twitter, and YouTube. A practical guide to getting the right dimensions every time.
Images ··8 min read
How to Convert PDF to Image (Complete Guide)
Learn how to convert PDF pages to images. A practical guide to extracting pages as JPG, PNG, or WebP files.
PDF ··7 min read
How to Rotate PDF Pages (Complete Guide)
Learn how to rotate PDF pages online. A practical guide to fixing upside-down and sideways pages in your PDF documents.
PDF ··7 min read
How to Create QR Codes for Business (Complete Guide)
Learn how to create QR codes for business. A practical guide to QR codes for marketing, payments, WiFi sharing, and customer engagement.
QR Codes ··8 min read
How to Use a Base64 Encoder/Decoder (Complete Guide)
Learn how to use a Base64 encoder and decoder. A practical guide to encoding and decoding text and binary data.
Text ··7 min read
How to Convert Text Case (Complete Guide)
Learn how to convert text between uppercase, lowercase, title case, sentence case, and more. A practical guide to text transformation.
Text ··8 min read
How to Count Words and Characters (Complete Guide)
Learn how to count words and characters in text. A practical guide to word counts, character limits, and writing constraints.
Text ··7 min read
How to Create Strong Passwords (Complete Guide)
Learn how to create strong passwords that are hard to crack. A practical guide to password security, managers, and best practices.
Security ··8 min read
How to Blur an Image for Privacy
Learn how to blur faces, license plates, and private details in photos and screenshots before sharing. A practical guide to doing it safely in your browser.
Images ··8 min read
How to Repeat Text Online
Learn how to repeat any text online. Duplicate words, sentences, or paragraphs with custom separators and numbering. A practical guide to doing it safely in your browser.
Text ··8 min read
How to Format, Validate, and Minify JSON
Learn how to format, validate, and minify JSON online. A practical guide to working with JSON safely in your browser.
Developer ··8 min read
How to Rotate and Flip Images: A Complete Guide
Wrong orientation is one of the most common photo problems. Here is how to rotate and flip images online to fix sideways photos.
Images ··8 min read
How to Create a Favicon for Your Website
A favicon is the small icon people see in their browser tab next to your site name. Here is how to create one and which sizes to use.
Images ··6 min read
How to Create a Text QR Code for Messages and Notes
A text QR code can share a note, message, or snippet with a scan. Here is how they work and when to use them.
QR Codes ··5 min read
How to Create Phone QR Codes for Calls and Contact Details
A phone QR code can start a call or save contact details with a scan. Here is how they work and what they contain.
QR Codes ··6 min read
How to Create Email QR Codes That Open the Right Address
An email QR code opens a message ready to send. Here is how they work, what to include, and how to generate one that opens the right app.
QR Codes ··6 min read
How to Generate QR Codes for WiFi Networks
Share your WiFi with guests by scanning instead of typing. Here is how WiFi QR codes work and how to generate one that connects.
QR Codes ··6 min read
How to Merge PDF Files Into One Document
Combining several PDFs into one file is simple — until pages end up in the wrong order. Here is how to merge PDFs cleanly and avoid common mistakes.
PDF ··7 min read
Spacebar Counter — Test and Improve Tapping Speed
A spacebar counter measures how many times you can hit the spacebar in a set time. Here is how the test works and what the numbers mean.
Games ··5 min read
How to Compress PDF Files Without Losing Quality
Large PDFs are hard to email and slow to share. Here is how to compress PDF files without losing quality.
PDF ··6 min read
Image Compression — Shrink Files Without Ruining Quality
Image compression is easy to overdo. Here is how to shrink files while keeping images useful — choose the right format and resize first.
Images ··7 min read
How to Convert PDF to Word Without Ruining the Layout
Converting a PDF to Word can give you an editable document or a mess of broken formatting. Here is why and which PDFs convert cleanly.
PDF ··8 min read
How to Add a Watermark to a Photo
A watermark can protect your images and build brand recognition — if you use it well. Here is how to add one and what settings to choose.
Images ··7 min read
JPG vs PNG vs WebP: Which Image Format Should You Use?
JPG, PNG, and WebP all handle images differently. Here is a plain-English guide to choosing the right format for photos, logos, and web images.
Images ··7 min read