Calculate the pressure difference between two points. This differential pressure calculator works for filters, ducts, pipes, tanks, pumps, cleanrooms, HVAC systems, flow checks, and pressure drop estimates.
High-side pressure:
Enter the upstream, inlet, positive, or higher pressure point.
Low-side pressure:
Enter the downstream, outlet, room, return, or lower pressure point.
Differential pressure:
The calculator subtracts the low-side pressure from the high-side pressure, then converts the result into common pressure units.
A differential pressure calculator is useful for HVAC filters, duct static pressure, cleanrooms, tanks, pipes, pumps, valves, flow meters, pressure drops, room pressurization, and process equipment checks.
This calculator estimates pressure difference only. Flow, restriction, density, temperature, turbulence, and equipment curves may also matter.
The basic differential pressure formula is:
ΔP = P₁ - P₂
Subtract the low-side pressure from the high-side pressure. Differential pressure equals P1 minus P2.
Differential pressure is the pressure difference between two points, such as before and after a filter, valve, duct, or pipe section.
Yes. A negative result means the pressure entered as the high side is lower than the pressure entered as the low side.
Common units include PSI, kPa, Pa, bar, inches of water column, millimeters of water column, mmHg, and inHg.