Fluid Mechanics Calculators

Orifice Flow Rate Calculator

Estimate incompressible flow through an orifice from pressure difference.

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Continue your analysis

These calculators use closely related quantities or commonly follow this calculation.

What is orifice flow rate?

Orifice Flow Rate is used in fluid mechanics calculators. This calculator evaluates estimate incompressible flow through an orifice from pressure difference. Enter the known engineering values, choose the units you are working in, and the result is converted consistently through the calculator engine.

Formula

flow_rate = discharge_coefficient * area * sqrt(2 * pressure_difference / density)
VariableMeaningUnits
discharge_coefficientDischarge Coefficientunitless, %
areaOrifice Aream², cm², mm², ft², in²
pressure_differencePressure DifferencePa, kPa, MPa, bar, psi
densityFluid Densitykg/m³, g/cm³, kg/L
flow_rateVolumetric Flow Ratem³/s, L/s, L/min

How to use the Orifice Flow Rate Calculator

  1. Enter each known engineering value in the calculator above.
  2. Select the unit that matches each value you entered.
  3. Press Calculate. The calculator converts inputs into consistent canonical units before evaluating the formula.
  4. Choose another output unit if you want to view the result in a different engineering unit.
  5. If the result belongs to a real project, log in and save the calculation with your project records.

Worked example

As a simple worked example, use Discharge Coefficient = 2 , Orifice Area = 3 m², Pressure Difference = 4 Pa, Fluid Density = 5 kg/m³. Enter those values above to reproduce the calculation and then change them to match your own design.

How to interpret the result

Use the result together with the assumptions, units and design limits for your project. Engineering calculations are only as reliable as their inputs, so verify values against drawings, measurements, datasheets or applicable standards before making a safety-critical design decision.

Engineering applications

  • Early-stage fluid mechanics calculators analysis
  • Checking hand calculations and design iterations
  • Comparing alternative engineering concepts

Common mistakes

  • Mixing incompatible units or entering a value in a different unit from the selected unit.
  • Using estimated inputs without recording the assumptions behind them.
  • Treating a simplified calculator result as a substitute for validation, testing or applicable engineering standards.