Practical guides, how-tos and comparisons to get the most out of our free online tools.
Minification has to preserve meaning, and the interesting part is the whitespace that carries meaning: the descendant combinator, the spaces inside calc(), the gap between two inline elements. Measured here on real files, including how much brotli was going to save you anyway.
Daniel Okonkwo · 16 min read
A checksum catches accidents. A cryptographic hash resists an attacker. A hash-table hash spreads keys. Three different jobs, three different families — and here is a CRC-32 collision constructed by hand in 0.11 seconds to show exactly why you cannot substitute one for another.
Daniel Okonkwo · 15 min read
The WCAG ratio is (L1 + 0.05) ÷ (L2 + 0.05), and L is relative luminance, not brightness. Green carries 71.52% of it and blue 7.22%, which is why pure blue on white passes at 8.59:1 while mid grey fails at 3.95:1. Here is the whole computation, run end to end.
Daniel Okonkwo · 15 min read
Crop factor is a ratio of sensor diagonals. It changes framing, not the lens — proved by computing field of view both ways — and it applies to the f-number as well as the focal length, which is the half most articles leave out.
Daniel Okonkwo · 11 min read
A stop is a factor of two in light. The f-number scale is powers of √2 for a reason you can derive in one line, EV = log2(N²/t) puts a number on it, and the three controls are equivalent in brightness only — never in the picture.
Daniel Okonkwo · 12 min read
Four variables set depth of field, and subject distance dominates the other three. The exact formulas, a computed table, why the circle of confusion is a decision rather than a measurement, and what "full frame has less depth of field" really means.
Daniel Okonkwo · 13 min read
Each of the five fields has one job, and attribution rarely breaks on the mechanism — it breaks on inconsistent values. Here are the naming rules, the case-sensitivity trap, and the internal-link mistake that destroys the original attribution.
Camille Laurent · 12 min read
K is invitations per user times the conversion rate of an invitation — two small numbers multiplied. Below 1 the loop is a finite multiplier worth 1/(1−K), and cycle time decides which loop actually wins.
Camille Laurent · 11 min read
Abandonment rate is one minus completed over created — and the figure quoted everywhere is an average across wildly different shops. The useful work is turning a percentage point of checkout completion into money, then discounting it for returns.
Camille Laurent · 10 min read
These tools multiply followers by an assumed rate per thousand, which makes them a CPM model under another name — and every input behind that rate is an assumption they never show you.
Camille Laurent · 10 min read
Both methods write off exactly the same total cost. Only the timing differs — and timing is worth money. A full year-by-year schedule for one asset, the crossover year, the switch-to-straight-line convention, and the present value of the tax deferral computed at 8%.
Camille Laurent · 11 min read
FIFO and LIFO are assumptions about which cost you attach to a sale, not about which box leaves the warehouse. Worked through identical purchases and sales, they move cost of sales, inventory, profit and tax — but operating cash before tax is identical to the cent.
Camille Laurent · 11 min read