.water-flow-calculator-container {
font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
background: #ffffff;
padding: 30px;
border-radius: 12px;
box-shadow: 0 4px 20px rgba(0,0,0,0.08);
border: 1px solid #e0e6ed;
}
.water-flow-calculator-container h2 {
color: #0066cc;
text-align: center;
margin-bottom: 25px;
font-size: 24px;
border-bottom: 2px solid #0066cc;
padding-bottom: 10px;
}
.calc-input-group {
margin-bottom: 20px;
}
.calc-label {
display: block;
font-weight: 600;
margin-bottom: 8px;
color: #333;
}
.calc-input-row {
display: flex;
gap: 10px;
align-items: center;
}
.calc-input {
width: 100%;
padding: 12px;
border: 1px solid #ccc;
border-radius: 6px;
font-size: 16px;
transition: border-color 0.3s;
}
.calc-input:focus {
border-color: #0066cc;
outline: none;
}
.calc-select {
padding: 12px;
border: 1px solid #ccc;
border-radius: 6px;
font-size: 16px;
background-color: #f9f9f9;
cursor: pointer;
}
.calc-button {
background-color: #0066cc;
color: white;
border: none;
padding: 15px 30px;
font-size: 18px;
font-weight: bold;
border-radius: 6px;
cursor: pointer;
width: 100%;
margin-top: 20px;
transition: background-color 0.3s;
}
.calc-button:hover {
background-color: #0052a3;
}
.results-box {
background-color: #f0f7ff;
border: 1px solid #cce5ff;
border-radius: 8px;
padding: 20px;
margin-top: 30px;
display: none;
}
.results-box h3 {
color: #004080;
margin-top: 0;
text-align: center;
}
.result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #dee2e6;
}
.result-row:last-child {
border-bottom: none;
}
.result-label {
font-weight: 500;
color: #555;
}
.result-value {
font-weight: 700;
color: #0066cc;
}
.method-selector {
display: flex;
justify-content: center;
gap: 20px;
margin-bottom: 30px;
background: #f5f5f5;
padding: 10px;
border-radius: 8px;
}
.radio-label {
display: flex;
align-items: center;
gap: 8px;
cursor: pointer;
font-weight: 600;
}
.article-section {
margin-top: 50px;
line-height: 1.6;
color: #444;
}
.article-section h3 {
color: #333;
margin-top: 30px;
}
.formula-box {
background: #f8f9fa;
border-left: 4px solid #0066cc;
padding: 15px;
margin: 15px 0;
font-family: 'Courier New', monospace;
font-weight: bold;
}
@media (max-width: 600px) {
.calc-input-row {
flex-direction: column;
}
.calc-select {
width: 100%;
}
.method-selector {
flex-direction: column;
align-items: flex-start;
}
}
function toggleMethod() {
var radios = document.getElementsByName('calcMethod');
var selected = 'dimensions';
for (var i = 0; i < radios.length; i++) {
if (radios[i].checked) {
selected = radios[i].value;
break;
}
}
if (selected === 'dimensions') {
document.getElementById('dimensionsInputs').style.display = 'block';
document.getElementById('volumeInputs').style.display = 'none';
} else {
document.getElementById('dimensionsInputs').style.display = 'none';
document.getElementById('volumeInputs').style.display = 'block';
}
document.getElementById('flowResults').style.display = 'none';
}
function calculateWaterFlow() {
var radios = document.getElementsByName('calcMethod');
var method = 'dimensions';
for (var i = 0; i < radios.length; i++) {
if (radios[i].checked) {
method = radios[i].value;
break;
}
}
var flowRateM3S = 0; // Base unit: Cubic Meters per Second
var formulaText = "";
if (method === 'dimensions') {
var diameter = parseFloat(document.getElementById('pipeDiameter').value);
var dUnit = document.getElementById('diameterUnit').value;
var velocity = parseFloat(document.getElementById('flowVelocity').value);
var vUnit = document.getElementById('velocityUnit').value;
if (isNaN(diameter) || isNaN(velocity) || diameter <= 0) {
alert("Please enter valid positive numbers for diameter and velocity.");
return;
}
// Convert Diameter to Meters
var diameterM = 0;
if (dUnit === 'mm') diameterM = diameter / 1000;
else if (dUnit === 'cm') diameterM = diameter / 100;
else if (dUnit === 'inch') diameterM = diameter * 0.0254;
else if (dUnit === 'ft') diameterM = diameter * 0.3048;
else diameterM = diameter;
// Convert Velocity to Meters/Second
var velocityMS = 0;
if (vUnit === 'mps') velocityMS = velocity;
else if (vUnit === 'fps') velocityMS = velocity * 0.3048;
else if (vUnit === 'mph') velocityMS = velocity * 0.44704;
else if (vUnit === 'kmh') velocityMS = velocity / 3.6;
// Area = PI * (d/2)^2
var area = Math.PI * Math.pow((diameterM / 2), 2);
// Q = A * v
flowRateM3S = area * velocityMS;
formulaText = "Q = A × v (Area × Velocity)";
} else {
var volume = parseFloat(document.getElementById('waterVolume').value);
var volUnit = document.getElementById('volumeUnit').value;
var time = parseFloat(document.getElementById('timeDuration').value);
var tUnit = document.getElementById('timeUnit').value;
if (isNaN(volume) || isNaN(time) || time <= 0) {
alert("Please enter valid numbers. Time must be greater than zero.");
return;
}
// Convert Volume to Cubic Meters
var volumeM3 = 0;
if (volUnit === 'liters') volumeM3 = volume / 1000;
else if (volUnit === 'gallons') volumeM3 = volume * 0.00378541;
else if (volUnit === 'ft3') volumeM3 = volume * 0.0283168;
else volumeM3 = volume; // m3
// Convert Time to Seconds
var timeSec = 0;
if (tUnit === 'sec') timeSec = time;
else if (tUnit === 'min') timeSec = time * 60;
else if (tUnit === 'hr') timeSec = time * 3600;
// Q = V / t
flowRateM3S = volumeM3 / timeSec;
formulaText = "Q = V / t (Volume / Time)";
}
// Convert Base Unit (m3/s) to Outputs
var resM3H = flowRateM3S * 3600;
var resLPM = flowRateM3S * 60000;
var resGPM = flowRateM3S * 15850.32314; // US Liquid Gallon
var resCFS = flowRateM3S * 35.3146667;
// Display Results
document.getElementById('resM3H').innerText = resM3H.toFixed(4) + " m³/h";
document.getElementById('resLPM').innerText = resLPM.toFixed(2) + " L/min";
document.getElementById('resGPM').innerText = resGPM.toFixed(2) + " gal/min";
document.getElementById('resCFS').innerText = resCFS.toFixed(4) + " ft³/s";
document.getElementById('resFormula').innerText = formulaText;
document.getElementById('flowResults').style.display = 'block';
}
Water Flow Rate Calculator
Millimeters (mm)
Centimeters (cm)
Inches (in)
Feet (ft)
Meters (m)
Meters per second (m/s)
Feet per second (ft/s)
Miles per hour (mph)
Km per hour (km/h)
Liters
US Gallons
Cubic Meters (m³)
Cubic Feet (ft³)
Seconds
Minutes
Hours
Calculation Results
Cubic Meters per Hour:
–
Liters per Minute (LPM):
–
US Gallons per Minute (GPM):
–
Cubic Feet per Second (CFS):
–
Primary Formula Used:
–
Understanding the Formula for Water Flow Rate Calculation
Calculating the water flow rate is essential for various applications, ranging from designing irrigation systems and plumbing networks to industrial fluid dynamics. The flow rate, typically denoted by the symbol Q, represents the volume of fluid that passes through a given surface per unit of time.
Method 1: Using Pipe Area and Velocity
The most common engineering formula for water flow rate calculation relates the cross-sectional area of a pipe to the velocity of the fluid moving through it. This is derived from the continuity equation.
Q = A × v
Where:
- Q = Flow rate (e.g., m³/s)
- A = Cross-sectional area of the pipe (m²)
- v = Average velocity of the fluid (m/s)
Since pipes are usually circular, the Area (A) is calculated using the diameter (D): A = π × (D/2)². Therefore, if you know the internal diameter of your pipe and the speed at which the water is traveling, you can determine exactly how much water is being delivered.
Method 2: Using Volume and Time
The second method is often referred to as the "bucket method" and is extremely practical for physical measurements in the field. If you catch water in a container of a known volume and measure how long it takes to fill, you can calculate the flow rate using a simple ratio.
Q = V / t
Where:
- Q = Flow rate
- V = Volume collected (e.g., Liters or Gallons)
- t = Time taken to collect that volume (e.g., Seconds)
Common Units of Measurement
Depending on your industry, you may encounter different units for flow rate. This calculator automatically converts between the most standard metrics:
- GPM (Gallons Per Minute): Standard in the US for plumbing and irrigation.
- LPM (Liters Per Minute): Common in countries using the metric system.
- CFS (Cubic Feet Per Second): Often used in hydrology and large-scale water management.
- m³/h (Cubic Meters per Hour): Standard for industrial pumps and municipal water supply.
Practical Example
Imagine you have a garden hose with an internal diameter of 1 inch (approx. 0.0254 meters). If the water is flowing at a velocity of 2 meters per second:
- First, calculate the radius: 0.0127 meters.
- Calculate Area: π × 0.0127² ≈ 0.0005067 m².
- Calculate Flow (Q): 0.0005067 m² × 2 m/s ≈ 0.0010134 m³/s.
- Convert to LPM: 0.0010134 × 60,000 ≈ 60.8 Liters per Minute.