Construction unit converter
Length, area, volume and weight across metric and imperial, including the site units the generic converters miss — cft, guntha, cent and cubic yards — plus feet-inch-fractions both ways.
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Every unit converts through its SI base, so results stay consistent in both directions.
Units this converter includes
- Length — mm, cm, m, km, inch, foot, yard, mile.
- Area — mm², cm², m², hectare, km², in², ft², yd², acre, and the Indian land units guntha and cent.
- Volume — ml, litre, m³, cm³, in³, cubic foot (cft), cubic yard, US gallon and imperial gallon.
- Weight — g, kg, tonne, quintal, ounce, pound and US ton.
Cubic feet appears as "cft" because that is what it is called on every site in South Asia, where sand and aggregate are ordered by the cft rather than the cubic metre. One cubic metre is 35.315 cft.
Feet, inches and fractions
The second panel handles the conversion that catches people out. Feet are base twelve and fractions are base sixteen, so mixing units mid-calculation produces errors that only show up at the saw. Enter feet, inches and a fraction to get decimal inches and millimetres, or work backwards from millimetres to the nearest sixteenth of an inch.
Read the full guide: Feet-Inch Math on Site: Stair Stringers Made Simple
No signal at the site? Take this calculation offline.
The feet-inch construction calculator for US and Canadian pros — stairs, rafters, roof pitch and framing, with diagrams for every shape. One-time payment, no subscription.
