These posts go a level deeper than the tool pages themselves — the reasoning behind a format choice, the edge cases that trip people up, and the small decisions (PNG vs. JPEG, AA vs. AAA contrast, when a semicolon breaks your JSON) that a one-line tool description doesn't have room for. New posts get added as tools are added or as recurring questions come up in tool feedback.
All posts
What Grade Do I Need on My Final? How the Math Works
The formula for the score you need on a final, worked step by step, plus why points-based classes answer the same question differently.
HOROSCOPE TOOLSWhat Your Life Path Number Means
How a life path number is calculated, why two calculators disagree, and what 1 to 9 plus the master numbers traditionally mean.
DEVELOPER TOOLSURL Encoding Explained: Why Spaces Become %20
Percent-encoding explained: the reserved set, encodeURI vs encodeURIComponent, why a plus sign turns into a space, and where %2520 comes from.
DEVELOPER TOOLSDoes Minifying CSS and JavaScript Actually Make a Site Faster?
Minification strips bytes, but your server already compresses. Here is what minifying really saves once gzip or Brotli is on.
DEVELOPER TOOLSBase64 Is Not Encryption: What It Actually Does
Base64 has no key and hides nothing. What it is genuinely for, why output grows 33 percent, what the equals signs mean, and why JWT payloads are readable.
DEVELOPER TOOLSMD5 vs. SHA-256: Which Hash Should You Use?
Three different jobs, three different answers. When MD5 is acceptable, when it is broken, and why passwords need neither MD5 nor SHA-256.
IMAGE TOOLSFavicon Sizes: Which Ones You Actually Need
The long favicon size lists are mostly obsolete. Four files cover almost everything. Exact link tags, what each one is for, and why yours did not update.
GENERATOR TOOLSAre QR Codes Safe to Scan? What a QR Code Can and Cannot Do
A QR code is encoded text, not a program. The real risk is the link you cannot read before you tap it. Plus why codes stop scanning.
IMAGE TOOLSWhy Images Get Blurry When You Resize Them
Resampling is not compression. Why downscaling is safe, why upscaling invents detail, and what to do about the softness afterwards.
IMAGE TOOLSHEIC vs. JPG: Why Your iPhone Photos Are Not JPEGs
Why your iPhone saves HEIC instead of JPEG, what it buys you, where it breaks, and the exact Camera setting that switches it back.
DEVELOPER TOOLSUnix Time Explained: Why Computers Count From 1970
The epoch that had to move twice, leap seconds, the milliseconds trap, and the exact instant 32-bit time runs out.
CONVERTER TOOLSPercentage Increase vs. Percentage Points
Five to ten percent is a 5 point move and a 100 percent rise at the same time. The formulas, basis points, and the traps in between.
CONVERTER TOOLSWhy Age Calculators Give Different Answers
Months have no fixed length, so the leftover months and days are a convention, not a fact. Three date libraries, three answers, one birth date.
GENERATOR TOOLSUUID vs. Random Number: Which Generator Do You Actually Need?
Two generators that look alike and solve different problems. The 128-bit layout, the version list after RFC 9562, and the security mistake to avoid.
CONVERTER TOOLSHow Currency Conversion Actually Works (And Why Rates Are Never Truly Live)
Mid-market, bid and ask, reference rates and the margin on top. Why the number in a converter is a snapshot, not a price you can trade at.
TEXT TOOLSWord Count vs. Character Count: Which One Actually Matters?
Different platforms measure length completely differently. Here's how word count, character count, and reading time are actually calculated.
CONVERTER TOOLSWhy Your Unit Conversion Doesn't Match: Rounding Errors Explained
Two converters, two slightly different answers for the same conversion. Here's why rounding errors happen, and which figure to trust.
GENERATOR TOOLSAre Online Password Generators Safe? How Client-Side Generation Works
A plain-language look at client-side vs. server-side password generators, what randomness actually means, and how to check a tool before you trust it.
HOROSCOPE TOOLSHow Do Compatibility Calculators Actually Work? Love, Numerology & Zodiac Explained
A plain-language breakdown of how letter-based, numerology-based, and zodiac-based compatibility calculators actually work — and how accurate they really are.
COLOR TOOLSA Practical Guide to WCAG Color Contrast
The real formula, the exact AA and AAA thresholds, the exemptions people misread, and why opacity breaks a naive contrast check.
DEVELOPER TOOLSJSON Formatting Best Practices for Developers
What the JSON spec permits and forbids, why large IDs are strings, and when pretty-printing is the right call.
GUIDEFree vs. Paid Online Tools: When Each Makes Sense
Not a features question. Who pays for the free tool, where your data goes, and what a wrong answer costs — a framework you can apply in two minutes.
IMAGE TOOLSHow to Compress Images Without Losing Quality
Lossy and lossless compression throw away different things. The mechanism, the quality slider myth, and the point where you should stop.
DEVELOPER TOOLS10 Browser-Based Tools That Save Developers Time
The real argument for a browser tool is that it runs client-side. Ten worth bookmarking, how to verify one, and where reaching for one is a mistake.