Enter the ambient pressure, the system pressure (the lower pressure under the suction cup), and the effective area into the calculator to determine the vacuum force. (Use consistent pressure units and reference—either both absolute, or both gauge relative to the same reference.)

Vacuum Force Calculator

Enter any 3 values to calculate the missing variable

Vacuum Force Formula

The following equation is used to calculate the Vacuum Force.

VF = (AP-SP) * A
  • Where VF is the vacuum force (lbf)
  • SP is the system pressure (psi)
  • AP is the ambient pressure (psi)
  • A is the effective vacuum area (in^2)

To calculate the vacuum force, subtract the system pressure from the ambient pressure, then multiply by the effective vacuum area.

What is a Vacuum Force?

Definition

In engineering applications (such as suction cups and vacuum handling), “vacuum force” is the net force created by a pressure difference across an area: the higher pressure side (often the surrounding/ambient air) pushes toward the lower pressure side (the “vacuum” region). This is different from the Casimir effect, which is a separate quantum phenomenon and is not what this calculator computes.

A vacuum force is dictated by the effective area and the pressure differential between the system and ambient pressures.

How to Calculate Vacuum Force?

Example Problem:

The following example outlines the steps and information needed to calculate the Vacuum Force.

First, determine the system pressure. For this example, the pressure under the suction cup is 2 psi (absolute).

Next, determine the ambient pressure. For a typical sea-level environment, ambient pressure is about 14.7 psi (absolute).

Next, determine the effective suction area. In this case, the effective area is 10 square inches.

Finally, calculate the vacuum force using the formula above:

VF = (AP-SP) * A

VF = (14.7-2) * 10

VF = 127 lb-f

FAQ

What is the difference between vacuum force and atmospheric pressure?

Atmospheric pressure is a pressure (force per unit area) due to the weight of the air. Vacuum force is a force created when there is a pressure difference across an area—for example, when the pressure under a suction cup is lower than the surrounding (ambient) pressure. The force is calculated from the pressure difference times the effective area.

How does the Casimir effect relate to vacuum force?

The Casimir effect is a quantum mechanical phenomenon where a force can arise between very closely spaced objects due to quantum fluctuations. It is sometimes described as a “vacuum” phenomenon, but it is not the same thing as suction-cup vacuum force from a pressure differential, and it is not modeled by the formula on this page.

Can vacuum force be used to generate power?

A pressure differential can do mechanical work (for example, moving an actuator or turning a turbine) as it equalizes, but creating and maintaining that pressure differential requires an energy source (such as a pump, compressor, or stored pressure/vacuum reservoir). These systems do not extract free “vacuum energy”; they convert energy from the device or source that produces the pressure difference.