Free online engineering calculators for piping, pumps, and process design work. No sign-up, no membership — open a tool and start calculating. Built and maintained by a process engineer with 27 years of oil, gas, and petrochemical design experience.
Piping & Flow
Size a line, work out the pressure drop, and convert fittings to equivalent length.
Pipe Pressure Drop Calculator
Pressure drop and velocity in a single line by the Darcy-Weisbach method. Enter flow rate, pipe size, and fluid properties in Imperial units.
Open calculator SI / MetricPipe Pressure Drop Calculator
The same Darcy-Weisbach pressure drop calculation set up in SI units for metric projects and international specifications.
Open calculator NFPA 54 · NewGas Pipe Sizing Calculator
Size a whole natural gas or propane system — meter, trunk, branches, and appliances — on a live network diagram. Covers 1/2 in. to 2 in. NPS.
Open calculator FittingsPipe Equivalent Length Calculator
Turn elbows, tees, valves, and reducers into equivalent straight pipe length so your pressure drop calculation accounts for the fittings.
Open calculatorPumps
Size a centrifugal pump and check that the suction side will work.
Pump Sizing Calculator & Cost Estimate
Differential head, hydraulic and brake power, and a budgetary cost figure for a centrifugal pump.
Open calculator Suction checkNPSH Calculator
Net positive suction head available for a centrifugal pump, so you can compare it against the vendor NPSH required and confirm your margin.
Open calculatorReference Data
The lookups you need before running any of the calculators above.
Steel Pipe Dimensions — NPS, OD, Sch, ID
Outside diameter, wall thickness, and inside diameter for carbon steel pipe by nominal size and schedule.
Open reference Fluid propertiesWater Density & Viscosity Calculator
Density and dynamic viscosity of water at your operating temperature — the two inputs the pressure drop and pump tools ask for.
Open calculatorDisclaimer
These calculators are developed by experienced engineers, but neither the engineers nor EngTank guarantees the accuracy of any result, and neither accepts responsibility for loss or damage arising from their use. Results should be checked by a qualified engineer before being used for design, procurement, or construction. If you are not sure how to run a calculation for your specific application, get in touch and we will help you work it out.