Liters per Minute (L/min)
Liters per Second (L/s)
Cubic Meters per Hour (m³/h)
Cubic Meters per Second (m³/s)
US Gallons per Minute (GPM)
US Gallons per Hour (GPH)
Cubic Feet per Minute (CFM)
Cubic Feet per Second (CFS)
US Gallons per Minute (GPM)
Liters per Minute (L/min)
Liters per Second (L/s)
Cubic Meters per Hour (m³/h)
Cubic Meters per Second (m³/s)
US Gallons per Hour (GPH)
Cubic Feet per Minute (CFM)
Cubic Feet per Second (CFS)
Converted Flow Rate:
0.00
Understanding Flow Rate Conversions
Volumetric flow rate is a critical measurement in fluid dynamics, engineering, environmental science, and various industrial applications. It defines the volume of fluid which passes per unit of time. Whether you are sizing a pump for an HVAC system, calculating irrigation requirements for agriculture, or monitoring municipal water supplies, converting between different flow rate units is a frequent necessity.
Common Flow Rate Units Explained
Flow rate units typically combine a volume unit (liters, gallons, cubic meters) with a time unit (seconds, minutes, hours). Here are the most common units used in this calculator:
GPM (US Gallons per Minute): The standard unit in the United States for plumbing, pumps, and irrigation systems.
L/min (Liters per Minute): Widely used in countries utilizing the metric system for water flow and industrial processes.
m³/h (Cubic Meters per Hour): Common in large-scale industrial applications, HVAC air handling, and water treatment plants.
CFM (Cubic Feet per Minute): The industry standard for airflow measurement in ventilation, heating, and air conditioning systems.
How to Calculate Flow Rate Conversions
To convert from one flow rate unit to another, you multiply the original value by a specific conversion factor. The general formula is:
Target Value = Source Value × Conversion Factor
Example: Converting GPM to L/min
If you have a pump rated at 10 GPM and need to know the flow in Liters per minute:
Since 1 US Gallon ≈ 3.78541 Liters, the formula is:
10 GPM × 3.78541 = 37.85 L/min
Conversion Factors Reference Table
The following table provides multipliers to convert from the units in the left column to the units in the top row. (Note: Values are approximate).
From \ To
L/min
GPM (US)
m³/h
CFM
1 L/min
1
0.2642
0.06
0.0353
1 GPM
3.7854
1
0.2271
0.1337
1 m³/h
16.6667
4.4029
1
0.5886
1 CFM
28.3168
7.4805
1.6990
1
Why Accurate Conversion Matters
Inaccurate flow rate calculations can lead to significant issues. In pump sizing, underestimating the required flow (GPM) can result in system failure, while overestimating can lead to excessive energy consumption and equipment wear. In HVAC, confusing CFM with m³/h can lead to poor air quality and inefficient temperature control. Always ensure your units match the specifications of your equipment.
function convertFlowRate() {
// Get input elements
var inputVal = document.getElementById("flowInput").value;
var fromUnit = document.getElementById("unitFrom").value;
var toUnit = document.getElementById("unitTo").value;
var resultContainer = document.getElementById("result-container");
var resultDisplay = document.getElementById("resultDisplay");
var unitDisplay = document.getElementById("unitDisplay");
var formulaDisplay = document.getElementById("formulaDisplay");
// Validate input
if (inputVal === "" || isNaN(inputVal)) {
alert("Please enter a valid numeric flow rate.");
return;
}
var val = parseFloat(inputVal);
// Conversion factors to Base Unit: Cubic Meters per Second (m³/s)
// This acts as a normalized bridge for all conversions.
var toBaseFactors = {
"m3s": 1.0,
"m3h": 1.0 / 3600.0,
"ls": 0.001,
"lmin": 0.001 / 60.0,
"gpm": 0.0000630901964, // US Gallons
"gph": 0.0000630901964 / 60.0,
"cfm": 0.000471947443,
"cfs": 0.0283168466
};
// Text labels for display
var unitLabels = {
"m3s": "m³/s",
"m3h": "m³/h",
"ls": "L/s",
"lmin": "L/min",
"gpm": "GPM",
"gph": "GPH",
"cfm": "CFM",
"cfs": "CFS"
};
// Calculate
// Step 1: Convert Input to Base (m³/s)
var baseValue = val * toBaseFactors[fromUnit];
// Step 2: Convert Base to Target
// We divide by the factor of the target unit relative to base
var finalValue = baseValue / toBaseFactors[toUnit];
// Formatting logic
// If the number is very small or very large, handle precision carefully
var formattedResult;
if (Math.abs(finalValue) < 0.0001 && finalValue !== 0) {
formattedResult = finalValue.toExponential(4);
} else {
// Adjust decimals based on magnitude
formattedResult = parseFloat(finalValue.toPrecision(6));
}
// Display results
resultContainer.style.display = "block";
resultDisplay.innerHTML = formattedResult;
unitDisplay.innerHTML = unitLabels[toUnit];
// Show simplified formula explanation
var ratio = toBaseFactors[fromUnit] / toBaseFactors[toUnit];
var cleanRatio = parseFloat(ratio.toPrecision(6));
formulaDisplay.innerHTML = "1 " + unitLabels[fromUnit] + " ≈ " + cleanRatio + " " + unitLabels[toUnit];
}