↳ Guides
Guides that actually go deep.
The math, the methods, and the reasoning behind the tools, written to be understood, not skimmed past.
How compound interest works (and why starting early wins)
Why a steady investment can multiply over decades. The formula, why compounding frequency barely moves the needle, and why time is your biggest lever.
Jun 8, 2026 · 2 min read
Flesch-Kincaid and readability scores explained: what is a good score?
Aim for a Flesch Reading Ease of 60 to 70, or grade 7 to 9, for general audiences. What each formula measures and how to lower your grade level.
Jun 13, 2026 · 2 min read
How long does it take to read 1,000, 5,000, or 10,000 words?
1,000 words is about 4 minutes, 5,000 about 21 minutes, 10,000 about 42 minutes. The full lookup table, plus how to adjust for your own pace.
Jun 13, 2026 · 2 min read
How to make a word cloud (free, online)
Paste text, filter stop words, size words by frequency. The full process, plus phrase clouds and PNG or SVG export for print.
Jun 13, 2026 · 2 min read
How long does it take to read aloud? Speaking time explained
Reading aloud averages 183 WPM; presenting runs slower at 120 to 150. What 1,000 words sounds like in minutes, and how to time a speech.
Jun 13, 2026 · 2 min read
What is keyword density? Formula and how to calculate it
Density equals keyword occurrences divided by total words, times 100. The formula, a worked example, and why chasing a target percentage backfires.
Jun 13, 2026 · 2 min read
What is URL encoding? Percent-encoding explained
Percent-encoding swaps unsafe URL characters for a % and two hex digits, so a space becomes %20. The character map and encodeURI vs encodeURIComponent.
Jun 13, 2026 · 2 min read
How long should a meta description be?
Aim for about 155 characters. How Google truncates by pixel width, and how to write a description that earns the click.
Jun 8, 2026 · 2 min read
Password strength explained: entropy, length, and why length wins
Strength is bits of entropy, not a sprinkle of symbols. Why length wins, and how many bits you actually need to stay safe.
Jun 8, 2026 · 2 min read
What is JSON? A practical guide to reading, validating, and fixing it
The six value types, the strict rules behind most errors, and how to format and validate JSON with confidence.
Jun 8, 2026 · 1 min read
How many words can you read per minute?
The average adult reads about 238 WPM silently. What the research actually says, and how to measure your own speed.
Jun 7, 2026 · 2 min read
Welcome to ToolBook
Why we are building a toolbox with visual results, plain-English explanations, and zero popups.
May 3, 2026 · 1 min read