Trade calculators & tools
Free calculators and lookups for every trade — plumbing, electrical, HVAC, concrete and more. No sign-up. Filter by trade, what it does, or who it's for.
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Hot water cylinder size
What size water heater do I need? Pick people + fuel, get the size.
Open tool →Drain slope / fall
Total drop over a run, with the code-minimum slope cited for your area.
In the worksConcrete calculator
How much concrete do I need? Enter length, width and thickness — get cubic yards, metres and bags.
Open tool →Gravel calculator
How much gravel do I need? Enter length, width and depth — get tons, cubic yards and tonnes for gravel, road base or sand.
Open tool →Asphalt calculator
How much asphalt do I need? Enter length, width and thickness — get the tons (and tonnes) of hot-mix asphalt to order for a driveway, path or car park.
Open tool →Board foot calculator
How many board feet do you have? Enter thickness, width, length and quantity — get the total board footage of lumber, plus the volume in cubic feet or metres.
Open tool →Roof pitch calculator
Enter rise and run — get the pitch (x:12), the roof angle, grade %, slope factor and rafter length.
Open tool →Roofing calculator
How much roofing do I need? Enter your roof footprint and pitch — get the area, the roofing squares and how many bundles of shingles to order.
Open tool →Stair calculator
Enter your floor-to-floor rise — get the number of risers, riser height, run, stringer length and angle.
Open tool →Voltage drop calculator
Will my wire drop too much voltage? Enter the current, run length and wire size — get the % drop checked against the 3% / 5% guideline, in AWG or mm², copper or aluminium.
Open tool →Pipe volume / capacity
Litres or gallons held in a length of pipe, by diameter.
Open tool →GPM / flow rate
Measure your water flow rate — time a container filling, get gallons per minute.
Open tool →Plumbing unit converter
mm↔inch, bar↔psi, °C↔°F, L/min↔GPM, L↔gal, m²↔ft² — instant, both ways.
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