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Fluid Mechanics

Differential Pressure Calculator

Differential pressure (ΔP) is the difference between two pressure values. This calculator provides two modes: a simple arithmetic mode (ΔP = P₁ − P₂) and a hydrostatic mode (ΔP = ρgh) for converting between differential pressure and liquid column height. It does not perform DP flowmeter calculations or square-root extraction.

TypeInteractive calculator — separate from unit conversions

Calculator

Result
ΔP (P₁ − P₂)50 kPa
|ΔP| magnitude50 kPa
DirectionP₁ > P₂

Formulas

Pressure difference
ΔP = P₁ − P₂
DP from static head
ΔP = ρ × g × h
Head from DP
h = ΔP / (ρ × g)

Diagram

Differential Pressure: ΔP = P₁ − P₂flowP₁P₂ΔP = P₁ − P₂hρ, gΔP = ρ × g × h

Worked example

P₁ = 300 kPa, P₂ = 250 kPa. What is the differential pressure? Also: density = 1000 kg/m³, h = 2 m, g = 9.80665 m/s². What is the DP from static head?

  1. 01ΔP = P₁ − P₂ = 300 − 250 = 50 kPa
  2. 02ΔP (hydrostatic) = ρ × g × h = 1000 × 9.80665 × 2
  3. 03ΔP = 19,613.3 Pa = 19.6133 kPa
Result

Arithmetic ΔP = 50 kPa. Hydrostatic ΔP for 2 m of water is 19,613.3 Pa (19.6133 kPa).

FAQ

Is this a DP flowmeter square-root extraction calculator?
No. This calculator performs simple pressure arithmetic and static head conversion. DP flow measurement with square-root extraction is not implemented.
Does this configure transmitters?
No. Transmitter configuration, calibration, and signal conditioning are outside the scope of this calculator.
Does this model wet legs or impulse lines?
No. Wet-leg compensation, dry-leg correction, and impulse line effects are not modelled.
Does this look up fluid density?
No. Density must be supplied directly for the hydrostatic mode. No fluid property lookup is performed.