Practical guides, how-tos and comparisons to get the most out of our free online tools.
Task lists are not in CommonMark. They are a GitHub Flavored Markdown extension, which is why the same file shows checkboxes in one place and literal brackets in another. The exact marker rule, what nesting does, and a table of what is CommonMark, what is GFM and what is neither — checked against both specs and four renderers.
Daniel Okonkwo · 11 min read
A URL slug is the readable, hyphenated part of a web address that names a page. Learn why slugs are lowercase, how they help SEO, and how to generate one from a title.
Daniel Okonkwo · 3 min read
"Break at spaces" fails in most of the world's writing systems. UAX #14 gives every character a line-break class; we looked ours up in Unicode 17.0.0 and ran a conforming implementation over no-break spaces, soft hyphens, zero-width spaces, URLs, Japanese and Thai.
Daniel Okonkwo · 13 min read
Convert square feet to square meters and back with the exact factor 0.0929, worked room-size examples in both units, and why area factors are the square of length factors.
Daniel Okonkwo · 3 min read
Turning a newline list into a comma list is trivial until an item contains a comma. RFC 4180's quoting rules, why a CSV field may contain a newline, why European spreadsheets use the semicolon, and what an empty item does to a round trip — every case run and printed.
Daniel Okonkwo · 13 min read
How much food a dog needs depends on body weight, age and activity level. Learn how to estimate daily portions from the bag's calorie count — and why your vet is the final word.
Marco Bianchi · 3 min read
An overpayment earns exactly the loan's rate, risk-free and after tax. On $200,000 at 5.00 percent over 25 years, $20,000 paid at the start saves $42,092 of interest; the same sum at year 16 saves $11,088; applied to the payment instead of the term it saves only $15,075.
Camille Laurent · 17 min read
The nth most common word appears about 1/n as often as the first. We counted six public-domain books, printed rank × frequency, fitted log frequency against log rank, and got slopes between -1.02 and -1.08 in all six languages — plus the two places the law breaks.
Daniel Okonkwo · 14 min read
The index quoted in the news is almost always a price index. At 5 percent price growth and a 2.5 percent reinvested yield, 30 years turn $10,000 into $43,219 on price and $90,656 on total return — the price measure misses 58.8 percent of the gain.
Camille Laurent · 13 min read
Taxable-equivalent yield = tax-free yield ÷ (1 − marginal rate). A 3.00 percent tax-free yield is worth 3.85 percent at a 22 percent marginal rate and 5.07 percent at 40.8 percent. The trap is that it is the marginal rate, surtaxes and social levies included — leaving them out costs 0.85 points of yield.
Camille Laurent · 15 min read
Why some years have a February 29, how the divisible-by-4, -100 and -400 rules combine, and how to check any year quickly.
Lena Hoffmann · 3 min read
Two reliable ways to find a triangle's area: half base times height when you know the height, and Heron's formula when you only know the three sides.
Lena Hoffmann · 4 min read