Guides & tips

Why PDFs get huge, and practical ways to shrink them for email and uploads — right in your browser, no software to install.

A plain-English explanation of Base64 — what it does, what it does not do, and the everyday cases where it matters.

What makes JSON valid, why formatting matters, and the most common mistakes that break your JSON — with quick fixes.

The handful of regular-expression building blocks that cover most real-world needs — explained with everyday examples.

A plain guide to the three formats that cover 99% of the web — when each one wins, and when to convert.

Why the old "add a symbol and a number" advice is wrong, and what actually makes a password hard to crack.

What a hash function actually does, why it is not encryption, and the everyday jobs hashes are perfect for.

What that big number like 1756400000 means, why programmers use it, and how to read it.

Why spaces turn into %20, which characters need escaping, and when to encode a URL.

The three parts of a JWT, what they are for, and the security mistakes to avoid.

How to read and write cron schedules — the five fields, the special characters, and copy-ready examples.

Combining PDFs into one document — the easy way, plus the privacy trap most online mergers fall into.

Target word counts for essays, blog posts, SEO, and social media — and why counting matters.

Why images are huge, how compression works, and how to shrink them for web and email while keeping them sharp.

What is inside a QR code, why some scan better than others, and tips for making one that always works.

Percent of a number, what percent one number is of another, and percentage change — with simple formulas.

How BMI is calculated, what the categories mean, and the important cases where BMI misleads.

Why your early payments are mostly interest, what amortization means, and how to pay less overall.

The common text cases, when to use each, and how to convert between them without retyping.

What a UUID is, why apps use them instead of counting 1, 2, 3, and how billions can be generated without ever clashing.

What #3b6ef6, rgb() and hsl() actually mean, how they relate, and which one to reach for when.

How automatic background removal works, when it struggles, and tips for a clean cutout — all in your browser.

Why your iPhone photos are HEIC, why some apps and PCs can not open them, and how to convert without losing quality.

When and why you would pull the audio out of a video, and how to convert MP4 to MP3 cleanly in your browser.

Work out sale prices and percentage off in your head, plus stacked discounts and the tricks retailers use.

What VAT is, how it differs from US sales tax, and how to add or remove it from a price.

What makes SVG different from JPG and PNG, when to use it, and when to convert it to a normal image.

The difference between resizing and cropping, why aspect ratio matters, and how to hit exact pixel dimensions.

Where that "Lorem ipsum dolor" text comes from, why designers use fake Latin, and when to use it.

Why age math is trickier than it looks, how leap years factor in, and how to get your age down to the day.

How to count days between two dates correctly, the off-by-one trap, and what a "D-day" really means.

What an exchange rate really is, why banks give you a worse one, and how to convert currencies accurately.

Why two systems exist, the conversions worth memorizing, and how to switch between them without mistakes.

How CSS gradients work, the difference between linear and radial, and tips for gradients that look good.

What dead and stuck pixels are, how to spot them in seconds, and what is normal vs. a deal-breaker.

How to check every key works, what "ghosting" and "N-key rollover" mean, and why gamers care.

The real differences that decide it, the transparency trap, and how to convert without a nasty surprise.

Why you would turn PDF pages into images, JPG vs PNG for the job, and how to do it privately.

The average human reaction time, what affects it, and how to measure yours accurately.

The difference between trimming and editing, why "stream copy" keeps quality, and how to do it in your browser.