About this site

Who runs it

SwizzWatches Calculators is run by Lokesh Rathore, who is responsible for what is published here. To report a wrong figure or ask a question, write to contact@swizzwatches.com.

Where the figures come from

Density, yield and conversion figures are printed on the calculator page that uses them, in a data table, with the source named. Each row says where its figure comes from: a named document, with the edition and section wherever the document has them. Where no document gives the figure, the row says so ('Not sourced', 'Arithmetic', 'Definitional') rather than borrowing a citation, and an undated source is marked undated.

27 cubic feet to the cubic yard is exact. 35.3147 cubic feet to the cubic metre is rounded; it comes from the exact definition 1 foot = 0.3048 metres. Where a figure is a trade convention rather than a measured constant — waste allowances, compaction factors, typical depths — the page says so.

How pages are checked

Every figure is checked against the document it is credited to before a page goes up. That checking has caught real errors, including a standard that had been cited but never opened and a specification quoted from a superseded edition. Drafts that did not survive it were not published.

When an error is found after publishing, the page is corrected and its source table updated. The concrete calculator, for example, was rebuilt after a review removed a density figure credited to ACI 318, which does not state it, made the worked example match what the calculator returns, and moved a saw-cutting rule to the section of ACI 302.1R-04 that contains it.

What this site is not

These calculators are estimating tools. They are not structural design, and they do not replace your supplier's own quantity advice or an engineer's specification for anything load-bearing. Check quantities against your supplier before ordering, and check structural requirements against your local building code.

Corrections

If a figure looks wrong, say so. Corrections with a source get made and the page's data table is updated. The contact address is on the Contact page.