CategoriesUtility

Utility Calculators

Helpful conversion tools and utility calculators for common DIY calculations. Convert units, calculate materials, and plan projects.

11 Calculators

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Unit conversions look trivial and are where the biggest errors hide.

These are the calculators that sit between the others: square feet to linear feet, cubic feet to cubic yards, tons to cubic yards, weights and volumes. Nothing about the arithmetic is hard. The mistakes come from converting between things that are not the same kind of measurement, most often treating a length as an area or a weight as a volume.

Square feet to linear feet is the clearest example. You cannot convert one to the other without a width, because area is length times width. Any answer that does not ask you for a width is guessing at one, which is why the same flooring order can come out 30% apart depending on the board width assumed.

Settle this before you calculate

Which quantity you actually have: Length, area, volume and weight are four different things. Converting between them always needs a second dimension or a density.
The width, for any linear conversion: Square feet to linear feet needs the material width. A 6 inch board and a 12 inch board give answers that differ by half.
Density, for any weight conversion: Tons to cubic yards depends entirely on the material. Concrete, gravel, soil and mulch differ by more than a factor of two.

Where the estimate goes wrong

Converting area to length without a width: There is no fixed factor. Divide the square footage by the material width in feet: 200 sq ft of 6 inch board is 200 ÷ 0.5, which is 400 linear feet.
Using one density for every material: A cubic yard is about 1.4 tons of gravel, 2 tons of concrete and 0.5 tons of dry mulch. Always convert with the material's own figure.
Mixing nominal and actual dimensions: A 2 by 4 is 1.5 by 3.5 inches and a 5/4 by 6 board is 5.5 wide. Nominal names are not measurements.