Practical guides, how-tos and comparisons to get the most out of our free online tools.
Area grows with the square of the diameter, so an 18-inch pizza is not half as big again as a 12-inch — it is more than twice. Price per square inch settles the argument; the crust and the toppings complicate it.
Lena Hoffmann · 11 min read
Lumens are what a lamp emits; lux is what lands on a surface. You cannot convert one to the other without an area, or without a distance and a beam angle. Anything that offers you a bare conversion factor is selling you a fiction.
Lena Hoffmann · 11 min read
One structural difference explains everything else: TAR does not compress, it only stacks; ZIP compresses each file on its own. Measured on 60 small source files, that is the difference between 1,809 bytes and 14,686.
Daniel Okonkwo · 12 min read
Salary is not the cost. The ticker applies no loaded-cost multiplier of its own, so the rate box is where you have to put it. And the number is for one comparison: a recurring meeting against the written update that would replace it.
Camille Laurent · 10 min read
Blur and pixelation are reversible — not by undoing the maths, but by guessing forwards. Against this tool's own blur and pixelate modes, a recovery attack returned the hidden value at rank 1 of 10,000. Both modes have since been removed. Here is what is left, and why it cannot be attacked the same way.
Daniel Okonkwo · 12 min read
Sixty-three days is measured from ovulation, not from the mating. Counted from a mating date the same pregnancy spreads over two weeks, because sperm survive for days and a bitch is often mated more than once. What the calculator does with that, and where its window stops four days early.
Marco Bianchi · 11 min read
Resting energy scales with weight to the power 0.75, not linearly, which is why a chart that doubles the food for a cat twice the weight is 83 kcal a day over. Neutered against intact, indoor against outdoor, and the boundary the arithmetic must not cross.
Marco Bianchi · 11 min read
The depth follows the job: a bare display, a planted tank whose roots need room, an under-gravel plate. Then comes the number people are unprepared for — substrate is what puts a filled tank past what a piece of furniture can hold. Plus why fine sand compacts and coarse gravel traps waste.
Marco Bianchi · 12 min read
Two to four inches, and the right end of that window depends on the material: bark takes 3, screened compost takes 1 to 2, and gravel takes 1. Here is the depth trade-off, the settling nobody buys for, and the bag conversion where the count goes wrong.
Marco Bianchi · 13 min read
The same 2,000 sq ft lawn at the same 1 lb of nitrogen per 1,000 sq ft takes 40 lb of a 5 percent blend or 4.3 lb of urea. Target nitrogen, not product — and read the bag count as shopping, not spreading.
Marco Bianchi · 12 min read
Four extensions, three of them the same box with different lids. Rename an XLSX to .zip and it opens — that single fact explains the whole family, and explains why XLS, which does not, is the one still causing trouble.
Daniel Okonkwo · 12 min read
The hourly rate is the small part. Minimum hours, the late-return surcharge, the ride home — and the question that changes the number most: casual help, or a declared employee? Six markets, named, with the thresholds that could be verified.
Camille Laurent · 12 min read