Differential Pressure Calculator

Differential Pressure Calculator: Predict Flow Meter Pressure Drop

Differential-pressure flow meters like orifice plates, venturis, and pitot tubes all rely on the same underlying physics: flow rate is proportional to the square root of the pressure drop across the device. This calculator inverts that relationship to predict the differential pressure a meter will produce at a given flow rate.

The Formula

dP = (Flow Rate / K)²

Worked Example

A flow meter with a K-factor of 2 is expected to pass a flow rate of 10 units.

dP = (10 / 2)² = 25 (in the pressure units the K-factor was calibrated to)

How to Use This Calculator

  1. Enter the expected flow rate through the meter.
  2. Enter the meter's K-factor from its calibration sheet.
  3. Click Calculate to get the expected differential pressure.

Related Calculations

Use with the Orifice Flow Calculator for a first-principles orifice sizing check.