Flow Rate and Velocity

These calculators find how much fluid moves and how fast. Get volumetric or mass flow, gpm, the flow a pipe can carry, velocity from flow and pipe size, orifice flow, and convert pressure in psi to feet of head.

Tools in this group

• Flow Rate Calculator — Find the volumetric flow rate from velocity and pipe size, from a volume and a time, from a channel's width and depth, or from mass flow and density.
• GPM Calculator (Gallons per Minute) — Work out gallons per minute from a bucket test, from pressure through a nozzle, from pipe velocity, or convert between gpm, L/min, cfs and m³/h.
• Mass Flow Rate Formula and Calculator — Apply the mass flow rate formula: density times volumetric flow, or density times area times velocity, with gas density from pressure and temperature.
• Orifice Flow Calculator — Use the orifice equation to find the flow through an orifice, its pressure drop, or the orifice size for a target flow, with or without a pipe upstream.
• Pipe Flow Calculator — Find how much a pipe can carry: enter the pressure available, the length and the pipe size, or switch to gravity flow for a sloped pipe running partly full.
• Pipe Velocity Calculator — Enter the flow rate and the pipe size or inside diameter to get the flow velocity, or switch to find the flow rate from a velocity.
• PSI to Feet of Head Calculator — Convert pressure in psi to feet of head, or feet of head to psi, for water or any liquid, and find the pressure at the bottom of a tank.