Water Flow Rate Calculator (Area x Velocity)
m²
cm²
in²
m/s
ft/s
cm/s
How to Calculate Flow Rate of Water
**Understanding Flow Rate**
Flow rate is a fundamental concept in fluid dynamics, representing the volume of fluid that passes through a given point per unit of time. It's a crucial measurement in many applications, from plumbing and irrigation to industrial processes and environmental monitoring. Understanding how to calculate flow rate allows for better system design, efficient resource management, and accurate performance analysis.
The most common way to calculate flow rate is using the following formula:
**Flow Rate (Q) = Area (A) × Velocity (v)**
Where:
* **Q** is the flow rate (often measured in cubic meters per second (m³/s), liters per minute (L/min), or gallons per minute (GPM)).
* **A** is the cross-sectional area through which the fluid is flowing (e.g., the area of a pipe's opening, measured in square meters (m²) or square inches (in²)).
* **v** is the average velocity of the fluid flow (e.g., meters per second (m/s) or feet per second (ft/s)).
Another common scenario involves calculating flow rate based on the volume of fluid collected over a specific time period:
**Flow Rate (Q) = Volume (V) / Time (t)**
Where:
* **Q** is the flow rate.
* **V** is the volume of fluid collected (e.g., cubic meters (m³), liters (L), or gallons (gal)).
* **t** is the time taken to collect that volume (e.g., seconds (s), minutes (min), or hours (hr)).
This calculator will help you determine flow rate using the first method (Area × Velocity), which is useful when you know the dimensions of the flow path and the speed of the fluid.
function calculateFlowRate() {
var area = parseFloat(document.getElementById("crossSectionalArea").value);
var areaUnit = document.getElementById("areaUnit").value;
var velocity = parseFloat(document.getElementById("averageVelocity").value);
var velocityUnit = document.getElementById("velocityUnit").value;
var resultDiv = document.getElementById("result");
if (isNaN(area) || isNaN(velocity)) {
resultDiv.innerHTML = "Please enter valid numbers for area and velocity.";
return;
}
// Convert area to square meters (m²) for consistent calculation
var areaInM2;
if (areaUnit === "m2") {
areaInM2 = area;
} else if (areaUnit === "cm2") {
areaInM2 = area / 10000; // 1 m² = 10000 cm²
} else if (areaUnit === "in2") {
areaInM2 = area * 0.00064516; // 1 in² = 0.00064516 m²
}
// Convert velocity to meters per second (m/s) for consistent calculation
var velocityInMps;
if (velocityUnit === "mps") {
velocityInMps = velocity;
} else if (velocityUnit === "fps") {
velocityInMps = velocity * 0.3048; // 1 ft/s = 0.3048 m/s
} else if (velocityUnit === "cmps") {
velocityInMps = velocity / 100; // 1 m/s = 100 cm/s
}
// Calculate flow rate in cubic meters per second (m³/s)
var flowRateM3ps = areaInM2 * velocityInMps;
// Convert to other common units for display
var flowRateLpm = flowRateM3ps * 60000; // 1 m³/s = 60000 L/min
var flowRateGpm = flowRateM3ps * 15850.3; // 1 m³/s = 15850.3 GPM
if (isNaN(flowRateM3ps)) {
resultDiv.innerHTML = "Calculation error. Please check inputs.";
} else {
resultDiv.innerHTML = "