Flow Rate Calculator
Calculate the flow rate of liquids through pipes and channels. Convert between velocity and volume flow rate easily.
Educational estimate. Calculator results are for planning and information only, not financial, tax, medical, legal, or engineering advice. Verify important decisions with official sources or a qualified professional.
Flow Rate Calculator
Calculate fluid flow velocity and volume
📐 Formula & Method
Continuity Equation
Q is volumetric flow rate in m3/s, A is cross-sectional area in m2, and v is average flow velocity in m/s.
Flow Unit Conversions
The calculator reports common water and process-flow units from the same base SI result.
📋 How to Use
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1
Determine the cross-sectional area of the pipe or channel.
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2
Measure or estimate the velocity of the fluid flow.
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3
Enter both values into the calculator.
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4
View the volume flow rate in m3/s, L/min, and m3/h.
🧮 Worked Examples
Validation case
Area 0.1 m2 with average velocity 1 m/s.
Understanding Fluid Dynamics: Flow Rate
Flow rate is a fundamental concept in fluid mechanics, representing the volume of fluid that passes through a given surface per unit of time. It is vital for designing irrigation systems, water supply networks, and industrial piping.
By calculating the flow rate, engineers can ensure systems are sized correctly to handle the required volume without exceeding practical velocity limits. This is a continuity-equation estimate and does not include pressure drop, viscosity, or pipe roughness.
🔬 Methodology & Accuracy
Formula: Uses the continuity equation for incompressible flow. Area must represent the active flow cross-section and velocity must be the average velocity over that section.
Data sources: Standard fluid mechanics continuity equation and SI unit conversions.
Last reviewed: May 2026 · General formula used: Continuity Equation · Accuracy: Results are precise to two decimal places using IEEE-754 double-precision arithmetic. Intended for educational and planning use only.
For informational purposes only. Results are estimates based on the inputs and formulas provided. For financial, tax, medical, or legal decisions, consult a qualified professional. Rates and regulations change — always verify current figures with official sources.