How to Split a PDF Into Pages, Ranges or Single Files
Split a PDF into single pages or pull out ranges like 1-3,5, free and in your browser. Learn which tool fits, plus the limits worth knowing.
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Guides on PDFs, file privacy, developer tools and the free tools on this site.
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PDF Tools
Rotate and Reorder PDF Pages Permanently, Free
Fix sideways scans and out-of-order pages. Rotate a PDF by 90, 180 or 270 degrees and rearrange or delete pages, all in your browser, with no upload.
Compare Two PDFs and Find Every Changed Word
Compare two PDFs for differences in your browser. See added and removed words highlighted, and learn what a text diff can and cannot catch.
How to Reduce a PDF's File Size: What Works and What Doesn't
Why PDFs get large, which fixes actually shrink them, and an honest look at what a browser-based compressor can and cannot do.
Merge PDF Files Without Uploading Them Anywhere
Combine several PDFs into one in your browser. No upload, no sign-up, no watermark, no file-size cap set by a server.
Image Tools
Compress Images for Faster Websites: A Practical Guide
Resize first, then compress, then pick the right format. A practical workflow for smaller JPG, PNG and WebP images, done free in your browser.
How to Resize an Image Without Losing Quality
What actually causes quality loss when you resize, why shrinking is safe and enlarging is not, and how to get a smaller file too.
Text & Writing Tools
Flesch Reading Ease Score: What the Number Means
How the Flesch Reading Ease formula works, what each score range means, how to improve a low score, and why a readability number is only a rough guide.
Developer Tools
SHA-256 Hash Explained: What It Is and When to Use It
What a SHA-256 hash is, why one changed letter changes everything, how it differs from encryption, and how to generate SHA hashes free in your browser.
Unix Timestamps Explained: Epoch Time to Date and Back
What a Unix timestamp is, why it starts in 1970, seconds versus milliseconds, time zones, and the 2038 problem. Convert epoch time free in your browser.
CSS Gradients, Shadows and Border Radius, Explained
Learn the syntax behind linear-gradient, box-shadow and border-radius, with the values to start from and free generators to preview and copy the CSS.
CSV vs JSON: When to Use Each Format (and How to Convert)
CSV and JSON solve different problems. Learn which fits your data, where each breaks down, and how to convert between them without losing information.
WCAG Color Contrast Ratio Explained: AA vs AAA
What a contrast ratio measures, the 4.5:1, 3:1 and 7:1 WCAG thresholds, and how to check a color pair so light gray text does not fail accessibility.
Base64 Encoding: What It Does and Why It Is Not Security
Base64 turns binary data into plain text so it can travel through text-only systems. It protects nothing. Here is how it works and when to use it.
UUID v4 Explained: How Random IDs Avoid Collisions
What a UUID guarantees, why version 4 is the common default, how unlikely a collision really is, and when a UUID is the wrong choice for your database.
How to Test a Regex Online Before You Ship It
A regex that looks right can still match too much, too little, or hang. Test it against real inputs in your browser before it reaches production.
Why Minified JSON Is Hard to Debug (and How to Fix It)
Minified JSON is great for machines and painful for people. Learn to format, validate and minify JSON, and spot the usual syntax errors fast.
QR Code Tools
Static vs Dynamic QR Codes: Which One Do You Need?
How static and dynamic QR codes differ, what each costs you over time, and how to choose before you print anything.
Calculators
How to Create a Freelance Invoice as a PDF, Free
What a freelance invoice should include, how to add sales tax correctly, and how to make a clean invoice PDF free in your browser. Not tax or legal advice.
Loan EMI Formula Explained, With a Worked Example
How the monthly payment formula works, why a longer term cuts the payment but raises total interest, and how to check your own numbers in a calculator.
Security & Privacy Tools
Is It Safe to Upload Confidential PDFs to Online Tools?
What happens to a PDF you upload to a free online tool, which risks are real, and how to process contracts and IDs without uploading them at all.
Strong Passwords vs Passphrases: Which Should You Use?
Random passwords or multi-word passphrases? Learn how entropy works, how long is long enough, and the limits of our own generator and strength meter.
Why Client-Side Tools Matter: Keep Files on Your Device
Most online file tools upload your data to a server. Here is why many tasks do not need that, and the honest trade-offs of doing it locally.
AES-256 Text Encryption Explained in Plain English
How AES-256-GCM and PBKDF2 turn a passphrase and a message into safe ciphertext in your browser, and what that protects against.
How to Password Protect a PDF (and Remove It Later)
Add or remove a PDF password in your browser, and learn what encryption protects, what it does not, and how to choose a strong password.
Fun & Productivity Tools
The Pomodoro Technique: Why 25 Minutes Works
Why the Pomodoro Technique uses 25-minute focus blocks and 5-minute breaks, how to run a session step by step, and when to adjust the timing.