General calculators & guides
Free general tools and plain-English guides for UK — each gives the answer fast and shows the working behind it.
About general calculations
Some calculations belong to every trade at once. Unit conversions are the obvious case — every site mixes metric and imperial somewhere, and a misconverted unit is the most preventable expensive mistake in construction. Flow rates, areas, volumes and pressures all cross trade boundaries the same way.
The general tools here are the shared toolbox: converters and calculators that do one job each, instantly, with the conversion factor or formula visible so you can verify rather than trust. They're term-neutral and unit-flexible because they serve every trade and every country the site covers.
Using the results
The discipline that makes conversions safe is writing down the units at every step — the calculator shows them at every step for exactly that reason. When a converted number feeds a decision that a code governs (a pressure rating, a clearance, a load), check the governing rule in your local edition after converting; the conversion is exact, but the rule that applies to it is local.