Pipe, Pump and Valve Calculators

Every calculator on the site, grouped by the job. Each one shows the formula and the steps with your numbers, lets you mix metric and US units, keeps its inputs in the link so you can share or repeat a result, and prints a dated record. Nothing you type is uploaded.

Pipe sizing and dimensions

• Pipe sizing calculator — the smallest PVC, copper, PEX, HDPE or steel size for a water flow, with a sizing chart.
• Pipe schedule chart — OD, wall thickness, ID and weight for every NPS and schedule.
• Gas pipe sizing calculator — natural gas and propane line sizes from the published sizing equations.
• Compressed air pipe sizing — air line size for a flow, pressure and allowed pressure drop.
• Steam pipe sizing calculator — steam line size by velocity, and condensate load.

Flow and velocity

• Flow rate calculator — volumetric flow from velocity and area, volume and time, or mass flow.
• Pipe flow calculator — the flow a pipe carries for an available pressure drop, and gravity (Manning) flow.
• Pipe velocity calculator — velocity in a pipe from the flow rate, or flow from velocity.
• GPM calculator — gallons per minute from a bucket test, a nozzle pressure or a unit conversion.
• Mass flow rate calculator — mass flow from density and volumetric flow or velocity.
• Reynolds number calculator — Re from velocity or flow, pipe size and fluid; laminar or turbulent.

Pressure drop and head loss

• Pressure drop calculator — Darcy-Weisbach friction loss with the friction factor and Reynolds number.
• Hazen-Williams calculator — water head loss, flow or pipe size by the Hazen-Williams equation.
• Orifice flow calculator — flow through an orifice, its pressure drop, or the bore for a flow.
• Moody chart — interactive Moody diagram and Darcy friction factor (Colebrook, Swamee-Jain).
• PSI to feet of head — pressure to head and head to pressure for any liquid, tank bottom pressure.

Valves and pumps

• Cv calculator — valve flow coefficient Cv and Kv for liquids and gases.
• Relief valve sizing calculator — required relief area and orifice letter for gas, steam or liquid.
• Pump horsepower calculator — hydraulic and brake horsepower, motor size and pool pump flow.
• NPSH calculator — net positive suction head available and the margin over NPSHr.

All results are estimates for planning and design checks; verify critical designs against the applicable standard and the manufacturer’s data. You may use the results in commercial work.