Engineering calculators
Each tool shows its formulas, assumptions and standards. Results are estimates only.
CivilConcrete Volume CalculatorFree concrete calculator for slabs, footings, columns, stairs and curbs. Get m³ or yd³, premix bags, cement, sand, aggregate and truck loads.CivilRebar Weight CalculatorFree rebar weight calculator for BS 4449 (6–40 mm) and ASTM A615 (#3–#18) bars: kg or lb, slab mesh bar counts, stock bars, laps, cut waste and cost.CivilBrick & Block CalculatorFree brick and block calculator: number of bricks or concrete blocks for walls with openings, plus mortar, cement bags and sand, in metric or imperial.CivilGravel & Aggregate CalculatorFree gravel calculator: tonnes, cubic metres and bags for driveways, paths and sub-base, with compaction, waste, truck loads and cost.CivilExcavation & Earthwork CalculatorFree excavation and earthwork calculator: dig volume for pits, trenches and sloped sides, soil swell and shrinkage, weight, truck loads, fill and cost.ElectricalOhm's Law & Power CalculatorFree Ohm's law and AC power calculator: volts, amps, ohms, watts, kW, kVA, kVAR and power factor for DC, single-phase and three-phase loads.ElectricalVoltage Drop CalculatorFree voltage drop calculator for copper and aluminium cables in mm² (IEC 60228) or AWG/kcmil (NEC): volts, % drop, 3%/5% limit check and smallest size.ElectricalCable Size CalculatorFree cable size calculator: smallest copper or aluminium cable (mm² or AWG) for voltage drop and short-circuit withstand, plus the rating it needs.MechanicalPump Power CalculatorFree pump power calculator: hydraulic, shaft and motor power in kW or hp from flow and head, with efficiency, motor size and annual energy cost.