Physics

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Orifice Flow Calculator.

Calculate ideal orifice flow from discharge coefficient, area, pressure drop, and density.

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Set your values

Results update as you type.

02 / ANSWER

Discharge coefficient

Orifice area

Pressure drop

Fluid density

Flow rate

0.000000m³/s

Results update automatically as you type.

Use Cases

Design flow restriction in piping systems

Engineers can estimate the flow rate through an orifice plate to design flow meters or restrictors in liquid pipelines.

Example: Calculate flow through a 0.005 m² orifice with a 50 kPa pressure drop in water (ρ=1000 kg/m³, Cd=0.62).

Verify flow measurement accuracy

Technicians can cross-check flow readings from orifice meters by inputting measured pressure drop and known orifice dimensions.

Example: Compare calculated flow with a flowmeter reading for a 0.01 m² orifice and 30 kPa drop in oil (ρ=850 kg/m³).

Frequently Asked Questions

What is the orifice flow formula used in this calculator?: The calculator uses the standard orifice flow equation: Q = Cd * A * sqrt(2 * ΔP / ρ), where Cd is the discharge coefficient, A is the orifice area (m²), ΔP is the pressure drop (Pa), and ρ is the fluid density (kg/m³).
What units should I use for the inputs?: Enter the discharge coefficient as a dimensionless number (typically 0.6-0.8), orifice area in square meters (m²), pressure drop in Pascals (Pa), and fluid density in kilograms per cubic meter (kg/m³).
Is this calculator suitable for compressible flow?: No, this calculator assumes incompressible flow. For gases with significant pressure drops, compressibility effects may require additional corrections.

Tips & Common Mistakes

Tips

Use a discharge coefficient (Cd) between 0.6 and 0.8 for sharp-edged orifices; consult standards for precise values.
Ensure pressure drop is measured across the orifice taps, not just the pipe, for accurate results.
For liquids, use the density at the actual temperature and pressure; for gases, use average density if compressible.
Double-check unit conversions: 1 bar = 100,000 Pa, 1 m² = 10,000 cm².

Common Mistakes to Avoid

Using diameter instead of area: the orifice area must be in m², not mm² or cm².
Forgetting to convert pressure drop to Pascals; using kPa or bar without conversion leads to errors.
Assuming Cd=1.0; real orifices have losses, so use a realistic coefficient.

Last updated: August 13, 2026

Use Cases

Design flow restriction in piping systems

Engineers can estimate the flow rate through an orifice plate to design flow meters or restrictors in liquid pipelines.

Example: Calculate flow through a 0.005 m² orifice with a 50 kPa pressure drop in water (ρ=1000 kg/m³, Cd=0.62).

Verify flow measurement accuracy

Technicians can cross-check flow readings from orifice meters by inputting measured pressure drop and known orifice dimensions.

Example: Compare calculated flow with a flowmeter reading for a 0.01 m² orifice and 30 kPa drop in oil (ρ=850 kg/m³).

Frequently Asked Questions

What is the orifice flow formula used in this calculator?

The calculator uses the standard orifice flow equation: Q = Cd * A * sqrt(2 * ΔP / ρ), where Cd is the discharge coefficient, A is the orifice area (m²), ΔP is the pressure drop (Pa), and ρ is the fluid density (kg/m³).

What units should I use for the inputs?

Enter the discharge coefficient as a dimensionless number (typically 0.6-0.8), orifice area in square meters (m²), pressure drop in Pascals (Pa), and fluid density in kilograms per cubic meter (kg/m³).

Is this calculator suitable for compressible flow?

No, this calculator assumes incompressible flow. For gases with significant pressure drops, compressibility effects may require additional corrections.

Tips & Common Mistakes

Tips

Use a discharge coefficient (Cd) between 0.6 and 0.8 for sharp-edged orifices; consult standards for precise values.
Ensure pressure drop is measured across the orifice taps, not just the pipe, for accurate results.
For liquids, use the density at the actual temperature and pressure; for gases, use average density if compressible.
Double-check unit conversions: 1 bar = 100,000 Pa, 1 m² = 10,000 cm².

Common Mistakes to Avoid

Using diameter instead of area: the orifice area must be in m², not mm² or cm².
Forgetting to convert pressure drop to Pascals; using kPa or bar without conversion leads to errors.
Assuming Cd=1.0; real orifices have losses, so use a realistic coefficient.

Use Cases

Design flow restriction in piping systems

Engineers can estimate the flow rate through an orifice plate to design flow meters or restrictors in liquid pipelines.

Example: Calculate flow through a 0.005 m² orifice with a 50 kPa pressure drop in water (ρ=1000 kg/m³, Cd=0.62).

Verify flow measurement accuracy

Technicians can cross-check flow readings from orifice meters by inputting measured pressure drop and known orifice dimensions.

Example: Compare calculated flow with a flowmeter reading for a 0.01 m² orifice and 30 kPa drop in oil (ρ=850 kg/m³).

Frequently Asked Questions

What is the orifice flow formula used in this calculator?

What units should I use for the inputs?

Is this calculator suitable for compressible flow?

No, this calculator assumes incompressible flow. For gases with significant pressure drops, compressibility effects may require additional corrections.

Tips & Common Mistakes

Tips

Use a discharge coefficient (Cd) between 0.6 and 0.8 for sharp-edged orifices; consult standards for precise values.
Ensure pressure drop is measured across the orifice taps, not just the pipe, for accurate results.
For liquids, use the density at the actual temperature and pressure; for gases, use average density if compressible.
Double-check unit conversions: 1 bar = 100,000 Pa, 1 m² = 10,000 cm².

Common Mistakes to Avoid

Using diameter instead of area: the orifice area must be in m², not mm² or cm².
Forgetting to convert pressure drop to Pascals; using kPa or bar without conversion leads to errors.
Assuming Cd=1.0; real orifices have losses, so use a realistic coefficient.