Differential Pressure

Calculate the difference between two pressure values and convert to various units. Useful for developers working with pressure sensors, HVAC, fluid dynamics, and data analysis.

Pressure A

Pressure B

Input Unit

Output Unit

Result

Please check your inputs.

Enter the first pressure value (e.g., from sensor A) in the input field and select its unit from the dropdown (psi, Pa, bar, mmHg, inH2O, etc.). Enter the second pressure value (e.g., from sensor B) and choose its unit. Click the 'Calculate' button to compute the difference (P1 - P2) and see the result displayed instantly. View the result in your chosen output unit, or switch to another unit to auto-convert. Use the copy button to save the result to your clipboard for use in code, reports, or further analysis.

📖 How to Use This Tool

Enter the first pressure value (e.g., from sensor A) in the input field and select its unit from the dropdown (psi, Pa, bar, mmHg, inH2O, etc.).

Enter the second pressure value (e.g., from sensor B) and choose its unit.

Click the 'Calculate' button to compute the difference (P1 - P2) and see the result displayed instantly.

View the result in your chosen output unit, or switch to another unit to auto-convert.

Use the copy button to save the result to your clipboard for use in code, reports, or further analysis.

📝 What Is Differential Pressure?

Differential pressure is the arithmetic difference between two pressure measurements. It is a critical parameter in many engineering and scientific applications: monitoring filter clogging in HVAC systems, measuring fluid flow velocity with Pitot tubes, detecting leaks in pipelines, and calibrating pressure sensors. This tool lets you quickly compute that difference without manual unit conversions, supporting over a dozen units like psi, kPa, bar, mmHg, and inches of water. By automating the calculation, it saves time and reduces errors, making it indispensable for developers integrating sensor data, HVAC technicians performing diagnostics, and engineers in fluid dynamics or industrial process control.

🧮 Formula

ΔP = P₁ – P₂, where ΔP is the differential pressure, P₁ is the first (typically higher) pressure value, and P₂ is the second (typically lower) pressure value. The tool automatically handles unit conversions so you can input P₁ and P₂ in different units—it converts both to a common base before subtraction and then displays the result in your selected output unit.

💡 Tips for Best Results

✨💡 Always ensure both pressure inputs are of the same type (both gauge or both absolute) to avoid offset errors in the differential result.

✨🔁 Before interpreting the result, confirm you're using a consistent unit system (SI or imperial) throughout your project's calculations.

✨📊 For HVAC filter monitoring, track differential pressure over time—a sudden increase indicates a clogged filter needing replacement.

✨🧪 In fluid dynamics, use a Pitot-static tube to measure dynamic pressure as DP = total pressure – static pressure; this tool gives you that number immediately.

❓ Frequently Asked Questions

What pressure units does this tool support?

It supports psi, Pa, kPa, MPa, bar, mbar, mmHg, cmH2O, inH2O, atm, torr, and more. You can mix input units—the tool auto-converts everything before subtraction.

Can I use differential pressure for gas and liquid applications?

Yes, differential pressure is a pure numeric difference and is independent of fluid type. As long as the two pressures are measured in the same context (e.g., both static pressures), the calculation is valid for any fluid.

Why does my result show a negative value?

If P₂ is larger than P₁, the difference (P₁ - P₂) will be negative. That's mathematically correct. You can swap the inputs to get a positive difference if that's more convenient for your use case.