Flow rate is a fundamental concept in fluid dynamics and engineering, representing the volume of fluid that passes through a given surface per unit of time. It's a crucial metric for understanding, monitoring, and controlling processes involving liquids or gases.
What is Flow Rate?
Mathematically, flow rate (often denoted by Q) is calculated as:
Q = V / t
Where:
Q is the flow rate
V is the volume of fluid
t is the time taken for that volume to pass
Units of Flow Rate
The units of flow rate depend directly on the units used for volume and time. Common units include:
Cubic meters per second (m³/s)
Liters per minute (L/min)
Gallons per minute (GPM)
Cubic feet per minute (CFM)
Our calculator allows you to input volume in cubic meters, liters, or US gallons, and time in seconds, minutes, or hours. The resulting flow rate will be displayed in the corresponding derived units (e.g., m³/s, L/min, gal/hr).
Applications of Flow Rate Calculations
Flow rate calculations are essential in a wide variety of fields:
Plumbing and Water Management: Determining the capacity of pipes, efficiency of pumps, and water usage.
Industrial Processes: Controlling the supply of reactants in chemical plants, monitoring fuel consumption, and managing material transport.
Aerospace and Automotive: Measuring fuel injection rates, airflow in engines, and coolant circulation.
Medicine: Administering medication through IV drips at precise rates.
Environmental Science: Measuring river discharge or wastewater flow.
How to Use the Calculator
To calculate the flow rate, simply:
Enter the total Volume of the fluid.
Select the appropriate unit for the volume (m³, L, or gal).
Enter the total Time it took for that volume to pass.
Select the appropriate unit for the time (s, min, or hr).
Click "Calculate Flow Rate".
Example Calculation
Let's say you want to find the flow rate of water filling a tank. You measure that 500 liters (L) of water flowed into the tank over a period of 5 minutes (min).
Volume = 500 L
Time = 5 min
Using the formula Q = V / t:
Q = 500 L / 5 min = 100 L/min
The flow rate is 100 liters per minute.
function calculateFlowRate() {
var volumeInput = document.getElementById("volume");
var timeInput = document.getElementById("time");
var volumeUnitSelect = document.getElementById("volumeUnit");
var timeUnitSelect = document.getElementById("timeUnit");
var resultDiv = document.getElementById("result");
var volume = parseFloat(volumeInput.value);
var time = parseFloat(timeInput.value);
var volumeUnit = volumeUnitSelect.value;
var timeUnit = timeUnitSelect.value;
if (isNaN(volume) || isNaN(time) || volume <= 0 || time 1000*60)
var flowRate_gal_per_hr = flowRate_m3_per_s * 9513.48; // m³/s to US gal/hr (1 m³ = 264.172 gal, 1 hr = 3600s => 264.172*3600)
resultDiv.innerHTML = "