Differential Pressure Calculator
Compute pressure difference between a high-side and low-side measurement in Pa, kPa, bar, or psi.
How to Use This Calculator
Enter high-side and low-side pressures
Provide the two pressure readings from your process, transmitter, or manometer.
Select the input and output units
Choose units that match your instruments. You can display the result in a different unit.
Click Calculate
The tool computes ΔP = Phigh − Plow and displays the result.
Formula
ΔP = Phigh − Plow
Where: ΔP is differential pressure, Phigh is upstream (or high-side) pressure, and Plow is downstream (or low-side) pressure.
Example: If Phigh = 350 kPa and Plow = 120 kPa, then ΔP = 230 kPa.
About Differential Pressure
Differential pressure (ΔP) is the difference between two pressure measurements. It is widely used to infer flow across restrictions, monitor filter health, measure level using sealed reference legs, and control process equipment.
Common Applications
- Filter fouling detection (rising ΔP indicates clogging)
- Orifice plate and Venturi flow measurements
- Tank level using differential transmitters
- Leak detection and pressure balancing
Tips for Best Results
- Ensure both sensors are referenced to the same baseline (absolute or gauge).
- Use consistent units across instruments to avoid conversion errors.
- Account for temperature effects and fluid density where relevant.
- Check transmitter calibration and zero before critical measurements.
Frequently Asked Questions
Can ΔP be negative?
Yes. If the low-side pressure exceeds the high-side pressure, the computed differential will be negative.
Which units should I choose?
Select the units that match your gauges or transmitter (Pa, kPa, bar, psi). You can output the result in any supported unit.
Does temperature affect ΔP?
The difference itself does not depend on unit temperature, but real systems may see pressure changes with temperature; consider density and thermal effects for precise work.
Is this suitable for airflow across filters?
Yes. Monitoring ΔP across filters is a common maintenance practice to indicate clogging.