Practical guides, how-tos and comparisons to get the most out of our free online tools.
Nobody negotiates a company car as a pay cut, but that is what the tax treatment makes it. Three countries value the same car by three completely different methods, one of them changed in 2025 in a way that nearly doubled the figure, and in all three an electric car is taxed at a fraction of the same vehicle with an engine.
Camille Laurent · 13 min read
Two documents that differ only in how many children exist produce two different JSON shapes, and no converter can tell them apart without a schema. Plus what this one really does with attributes, mixed content and whitespace — and the one thing it still cannot record.
Daniel Okonkwo · 15 min read
The migration, the tooling change, the process fix: the most common business case there is and the least documented. The value is avoided cost plus recovered time — and on a $130,000 migration, 60.5 % of the recovered hours have to be genuinely redeployed before the five-year net present value even reaches zero.
Camille Laurent · 18 min read
Four European countries, four different answers to the same question: at what point does a small business stop being treated as small? The thresholds matter less than the clock attached to them — some bite the day you cross, others wait for January.
Camille Laurent · 13 min read
A day rate is a price, not an income. Between the invoice and the bank balance sit six separate subtractions, and in three European countries they are ordered differently, capped differently and paid at different times. Here is the whole chain with the 2026 figures that are verifiable and an honest note on the ones that are not.
Camille Laurent · 15 min read
The gross salary on the contract is not the price of the job. Three European countries, the same monthly gross, and the employer's compulsory bill differs by nearly a factor of two — because of ceilings, not because of headline rates. Here is the 2026 arithmetic, line by line.
Camille Laurent · 13 min read
The same two orders come out as five columns from one converter and ten from another, and neither is wrong. Dotted paths, arrays of scalars, arrays of objects and records with different keys — four decisions, made for you, usually silently.
Daniel Okonkwo · 16 min read
Quoted delimiters, embedded newlines, ambiguous types, duplicate headers and encoding. Each one was run through the converter and the exact output is printed here — including the two cases it does not rescue.
Daniel Okonkwo · 15 min read
It throws away everything after the cut-off, ignores the time value of money, and ranks a project that returns early and then dies above one that returns steadily. Computed: payback prefers the worse project by 1.33 years while net present value prefers the better one by $19,571. And the popular shortcut — one divided by the payback — overstates the true return by 17 points on a five-year asset.
Camille Laurent · 17 min read
The coverage ratio is the gate, the guarantee is the second price and the rate is an output. On a 400,000 loan, cutting the rate by a full point moves the coverage ratio by 0.018 — while two extra years of term move it by 0.216. The whole negotiation is in the wrong place.
Camille Laurent · 19 min read
Framingham, SCORE2 and the pooled cohort equations use overlapping but different inputs and were calibrated on different populations, so the same person gets three different percentages. Here is what each one asks for and what the number means.
Sofia Nunes · 6 min read
Everyone asks from what turnover a side activity starts to pay. The question has no answer, because the number that decides it is what an hour of yours is worth — and once that is in the calculation, the threshold stops being a sum of money and becomes a rate per hour that does not move with volume.
Camille Laurent · 9 min read