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MJ
Md Jony Islam
Last updated: Jun 14, 2026

Flow Rate Calculator

Calculate the flow rate of liquids and gases using velocity, cross-sectional area, or volumetric flow. Step-by-step solutions for pipes, channels, and ducts.

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Volume

Time

Pipe Properties (Optional)

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Flow Rate Calculator

Calculate the flow rate of liquids and gases using velocity, cross-sectional area, or volumetric flow. Step-by-step solutions for pipes, channels, and ducts.

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Flow Rate calculator:

This Flow Rate Calculator will work out the volumetric or mass flow of liquids and gases with the use of this calculator. Type in the velocity of entry, the area of the pipes/ducts, or the density of the fluid you want to apply to calculate the flow rate, velocity, and discharge using step-by-step calculations.

Volumetric Flow Tools formula

The flow rate calculator assists engineers, students, and technicians in calculating the movement of liquids and gases in pipes, channels, and ducts. The flow rate refers to the amount of fluid or mass of fluid that is moving through a cross-section in a given time.

Fluid velocity (v), cross-sectional area (A), and volumetric/mass flow rate (Q, ṁ) can be entered by the user. The calculator determines volumetric flow rate (Q = A × v), mass flow rate (ṁ = 4 × Q), and fluid velocity with the help of standard fluid mechanics equations.

Flow rate varies with diameter of pipe, area, and velocity, which is readily analyzed step-by-step to show how water is distributed through a water system, HVAC ducts, industrial piping, and open channels. SI units are allowed: m 3/s, L/s, m/s, kg/s, m 2. The tool is suitable for mechanical, civil, and chemical engineers and students, and it guarantees the correct analysis of energy and fluid flow.

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Work & Installation — Input to Output Summary

Input:

  • Velocity (v)
  • Cross-sectional area (A)
  • Fluid density (ρ) for mass flow
  • Units: m/s, m², kg/m³

Processing:

  • Volumetric flow rate: Q = A × v
  • Mass flow rate: ṁ = ρ × Q
  • Fluid velocity: v = Q / A
  • Validate input values and units

Output:

  • Volumetric flow rate (Q)
  • Mass flow rate (ṁ)
  • Fluid velocity (v)
  • Step-by-step formulas and calculations

Testing and Final Adjustments

Test examples:

  • Pipe: diameter 0.1 m, velocity 2 m/s → Q ≈ 0.0157 m³/s
  • Water density 1000 kg/m³ → ṁ ≈ 15.7 kg/s
  • Open channel: area 0.5 m², velocity 1.2 m/s → Q = 0.6 m³/s
  • Edge cases: A = 0 → Q = 0, v = 0 → Q = 0
  • Units validation: m³/s ↔ L/s, m² ↔ cm², m/s ↔ ft/s
  • Step-by-step clarity for students and engineers
  • Mobile/desktop UX: numeric keypad, labels, dropdown for units
  • Include examples: water pipelines, HVAC ducts, chemical process piping, river flow
  • SEO metadata: "Flow Rate Calculator," "Pipe Flow Tool," "Volumetric & Mass Flow Calculator," schema markup
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Frequently Asked Questions - Flow Rate Calculator:

Flow rate is the volume or mass of fluid passing through a cross-section per unit time.
Q = A × v, where A is the cross-sectional area and v is the fluid velocity.
ṁ = ρ × Q, where ρ is fluid density and Q is volumetric flow rate.
Yes, v = Q / A.
Volumetric flow in m³/s or L/s, velocity in m/s, area in m², mass flow in kg/s.
Yes, the calculator supports both gases and liquids, including air, water, and steam.
Mechanical, civil, chemical engineers, HVAC technicians, and students analyzing fluid flow.
Yes, all formulas and intermediate steps are displayed for clarity.
Flow rate determines the capacity and efficiency of fluid transport systems in engineering applications.
Yes, by providing the cross-sectional area and velocity, it can calculate flow in open channels or conduits.
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