Immersed Weight Calculator

Apparent Weight in a Fluid

When an object is fully submerged, the fluid exerts an upward buoyant force. The immersed weight (apparent weight) is the true weight minus that buoyant force. This is useful in hydraulics, diving, and material handling in liquids.

Formula

$$W_{immersed} = mg - \rho_f V g$$

Here $m$ is object mass, $V$ is displaced volume, $\rho_f$ is fluid density, and $g$ is gravitational acceleration. The buoyant force is $\rho_f V g$.

Practical Notes

Enter mass directly or derive it from object density and volume. For full submersion, displaced volume equals object volume. If the object floats, only part of the volume is submerged and a different analysis applies.

Frequently Asked Questions

What is immersed weight?

Immersed weight is the net downward force you measure when an object is fully submerged. It equals weight in air minus buoyant force.

Why is volume required if I enter mass?

Buoyancy depends on displaced fluid volume, not mass alone. Mass and volume together define how strongly the fluid pushes upward.

What fluid density should I use for water?

Fresh water is about 1000 kg/m³ at room temperature. Seawater is roughly 1025 kg/m³.

Can immersed weight be negative?

If buoyant force exceeds weight, the object rises. This calculator reports the algebraic immersed weight, which can be negative for buoyant objects.

Does this apply to partially submerged objects?

This tool assumes full submersion. For floating objects, use only the submerged portion of volume in the buoyancy term.

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Immersed Weight Calculator

Apparent Weight in a Fluid

Formula

Practical Notes

Frequently Asked Questions

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