Pump Flow Rate Calculation Online

Pump Flow Rate Calculator

Calculate volumetric flow rate based on pipe diameter and velocity.

Imperial (Inches / ft/s) Metric (mm / m/s)

Calculation Results:

Gallons Per Minute (GPM):

Liters Per Minute (L/min):

Cubic Meters Per Hour (m³/h):

Cubic Feet Per Second (CFS):

How to Use the Online Pump Flow Rate Calculator

Calculating the flow rate of a pump is essential for designing irrigation systems, plumbing networks, and industrial processes. This online tool allows you to determine how much fluid is moving through a pipe based on the pipe's interior dimensions and the speed of the fluid.

The Pump Flow Rate Formula

The fundamental equation for volumetric flow rate is Q = A × v, where:

  • Q: Volumetric flow rate
  • A: Cross-sectional area of the pipe (π × r²)
  • v: Velocity of the fluid

Common Fluid Velocity Standards

When designing a system, certain fluid velocities are recommended to prevent pipe erosion or sediment buildup:

Application Recommended Velocity (ft/s) Recommended Velocity (m/s)
Suction Lines 2 – 4 ft/s 0.6 – 1.2 m/s
Discharge Lines 5 – 10 ft/s 1.5 – 3.0 m/s
General Water Service 4 – 7 ft/s 1.2 – 2.1 m/s

Practical Calculation Example

Imagine you have a pipe with an internal diameter of 3 inches and a fluid velocity of 6 feet per second:

  1. Calculate Area: (π × 1.5²) = 7.068 square inches.
  2. Convert Area to square feet: 7.068 / 144 = 0.0491 sq ft.
  3. Calculate Flow (CFS): 0.0491 sq ft × 6 ft/s = 0.2946 CFS.
  4. Convert to GPM: 0.2946 × 448.83 = 132.22 GPM.
function updateLabels() { var unit = document.getElementById("calcUnit").value; var labelD = document.getElementById("labelDiameter"); var labelV = document.getElementById("labelVelocity"); if (unit === "imperial") { labelD.innerHTML = "Pipe Inner Diameter (inches)"; labelV.innerHTML = "Fluid Velocity (ft/s)"; } else { labelD.innerHTML = "Pipe Inner Diameter (mm)"; labelV.innerHTML = "Fluid Velocity (m/s)"; } } function calculateFlowRate() { var unit = document.getElementById("calcUnit").value; var dia = parseFloat(document.getElementById("pipeDiameter").value); var vel = parseFloat(document.getElementById("flowVelocity").value); if (isNaN(dia) || isNaN(vel) || dia <= 0 || vel <= 0) { alert("Please enter valid positive numbers for diameter and velocity."); return; } var area, flowCFS, flowM3S, gpm, lpm, m3h, cfs; if (unit === "imperial") { // dia in inches, vel in ft/s var radiusFt = (dia / 2) / 12; area = Math.PI * Math.pow(radiusFt, 2); // sq ft cfs = area * vel; // cubic feet per second gpm = cfs * 448.831; lpm = gpm * 3.78541; m3h = cfs * 101.94; // approx } else { // dia in mm, vel in m/s var radiusM = (dia / 2) / 1000; area = Math.PI * Math.pow(radiusM, 2); // sq meters var m3s = area * vel; // cubic meters per second m3h = m3s * 3600; lpm = m3s * 60000; gpm = lpm / 3.78541; cfs = m3s * 35.3147; } document.getElementById("resGPM").innerHTML = gpm.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); document.getElementById("resLPM").innerHTML = lpm.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); document.getElementById("resM3H").innerHTML = m3h.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); document.getElementById("resCFS").innerHTML = cfs.toLocaleString(undefined, {minimumFractionDigits: 4, maximumFractionDigits: 4}); document.getElementById("resultsArea").style.display = "block"; }

Leave a Comment