A sheet for every quantity
An ordinary converter answers the question «how many» and stops there. But someone looking up a unit almost never wants the coefficient alone: he needs to see where the number came from, what measures it, how to write it on a drawing without an error, and why the neighbouring trade writes the same thing differently. That is why each unit here has a sheet, not a row in a table.
The sheets share one skeleton — from the plate with the international symbol to the historical section — and differ in their interactive stands: the watt has its own diagram, the okta another, the weld leg a third. The skeleton means you never hunt twice for the same field; the stand keeps the reference from turning into a graveyard of tables.
Four rules by which a sheet is written
Definitions of the SI units and the exact values of the constants follow the SI Brochure of the International Bureau of Weights and Measures. Conversion factors for non-SI units follow NIST SP 811. Rules of writing and drawing conventions follow the standards in force, with the number given in the footer of the sheet. Trade norms follow their own codes, and the text always says whose norm it is: the track engineer, the road builder and the roofer write the same quantity differently, and not out of carelessness.
Historical values are given as a range, not as a single number: the Roman foot varied from 293 to 334 millimetres, and pretending it had one exact value would be lying to the reader for the sake of a tidy table.
Seven sections, always in the same order
A universal slider that «multiplies by a coefficient» explains nothing. A quantity becomes clear when you can see what it governs: for a slope it is the wheelchair on the ramp and the water in the channel, for a weld leg the quadratic growth of metal in section, for the okta the eight parts of the sky above the observer, for an accuracy class the sector of tolerance that turns with the needle. Such stands cannot be made from a template, so each is drawn separately, with its own scenes and its own thresholds at which the figure turns red.
The archive by section
The queue is set by readers. If the unit you work with is not here, write and say what exactly you measure with it and where colleagues get confused: that makes a better sheet than a standard does.
Write to the project →Thirty-six locales and one layer that never changes
Every sheet has a layer that is translated into no language at all: the symbol of the unit, the marks of drawing convention, standard numbers, the figures of a series. The watt stays W, the okta stays okta, the weld leg stays z, and the plate of the sheet always carries the international symbol, not the local word. This is for the reader who opens the sheet in his own language but works with foreign documentation.
Everything else is translated: the prose, the captions of the stands, the descriptions of instruments, the historical section. The list of locales is closed and does not grow — thirty-six, including three written from right to left and Latin for the historical sheets.