Practical guides, how-tos and comparisons to get the most out of our free online tools.
(1 + r/n)^n rises with n but converges on e^r. At 6 percent, monthly and continuous compounding differ by $1.59 on $10,000 over a year. At 24 percent the same gap is $30.07, and over thirty years it is 7.4 percent of the balance.
Camille Laurent · 11 min read
A link becomes text with its destination deleted, a nested list loses its hierarchy, a table becomes a row of words. Then the technical half: markdown has no single spec, and a regex stripper mangles a filename, a multiplication sign and the inside of a code block — all shown against a real parser.
Daniel Okonkwo · 12 min read
Case, whitespace, punctuation and diacritics: four policies, six real sentences, and the answer changes with each one. Then the harder half — reversing a string is itself undefined, and code-unit reversal breaks emoji and detaches accents, demonstrated in Node.
Daniel Okonkwo · 12 min read
Greedy against lazy on the same string, the dot that skips newlines, $& and $$ in the replacement, a reused /g regex that silently skips a row, and why /i knows nothing about Turkish i. Every failure run in Node, with a count-then-replace routine that catches them.
Daniel Okonkwo · 14 min read
Code-unit order, natural order and locale collation run on the same list in Node, with the outputs printed. Why Zebra beats apple, why item10 beats item9, and why ä sits next to a in German but after z in Swedish.
Daniel Okonkwo · 12 min read
CPL is spend divided by leads, and alone it means almost nothing, because a lead is whatever you decided to call one. Worked here: a channel with twice the CPL producing half the CAC, and the redefinition that moves CPL fivefold without moving CAC at all.
Camille Laurent · 14 min read
Density counted occurrences because retrieval once counted occurrences. TF-IDF, then BM25 with its saturation curve, then embeddings replaced it. Here is the same 800-word page scored three ways, and why the three disagree.
Camille Laurent · 13 min read
Schema.org markup buys eligibility for a rich result, never a guarantee and never a ranking boost. Here is which types still produce something visible in 2026, what each one requires, and the one rule that gets sites penalised.
Camille Laurent · 15 min read
The two directions fail in opposite ways. PNG to JPG silently flattens transparency onto a background colour the converter chooses — we got white from one tool and black from another on the same file. JPG to PNG recovers nothing and cost up to 11.4 times the bytes.
Daniel Okonkwo · 12 min read
A visible mark lives in the pixels, so it survives every copy — and degrades the image for every honest viewer at the same time. Measured: what a corner mark costs, what a tiled mark costs, and how each compares to metadata credit, Content Credentials and invisible watermarking.
Daniel Okonkwo · 14 min read
Five files cover every consumer that exists: the tab, the bookmark, the pinned tile, the Android home screen and the iOS home screen. The twenty-file lists are a dead browser matrix — with measurements showing what a 16-pixel icon can and cannot hold.
Daniel Okonkwo · 13 min read
Unix time counts seconds since 1970 while deliberately ignoring leap seconds, which is why it is not a count of elapsed physical seconds. Here is what that trade buys, what a leap second does to the counter, the exact instant a signed 32-bit counter overflows, and the factor-of-1000 bug that lands you in 1970 or the year 58589.
Daniel Okonkwo · 17 min read