Immersed Weight Calculator — Apparent Weight in Fluid
Find the apparent (felt) weight of any object fully submerged in a fluid — fresh water, sea water, mercury, oil, or a custom density — using Archimedes' principle.
kg
kg/m³
Fluid
Weight felt while fully submerged in the fluid
- 1
Actual weight in air
5 × 9.80665 = 49.033 - 2
Object volume
5 ÷ 2,700 = 0.001852V = m / ρ_object (m³) - 3
Buoyant force
1,000 × 0.001852 × 9.80665 = 18.16 - 4
Apparent (immersed) weight
49.033 − 18.16 = 30.873
How does this calculator work?
Apparent (immersed) weight = m·g·(1 − ρ_fluid/ρ_object). Enter the object's mass and density plus the fluid's density to get the weight felt while submerged, the buoyant force, and the percentage weight reduction from Archimedes' principle.
Formula
How this is calculated
When an object is submerged in a fluid it displaces fluid equal to its own volume. The fluid pushes back with an upward buoyant force equal to the weight of the displaced fluid — Archimedes' principle: F_b = ρ_fluid·V·g. The apparent weight is the actual weight minus that buoyant force: W_apparent = m·g − F_b. Because V = m/ρ_object the formula simplifies to W_apparent = m·g·(1 − ρ_fluid/ρ_object). If the object's density is lower than the fluid's, the buoyant force exceeds the actual weight and the net result is negative — meaning the object floats.
This calculation assumes the object is rigid and fully submerged (not partially floating), the fluid is uniform and incompressible, and there are no surface-tension or viscosity effects. Real-world measurements may differ slightly due to dissolved gases, temperature-dependent fluid density, and irregular shapes that affect pressure distribution.
Frequently asked questions
Water pushes upward on the submerged object with a buoyant force equal to the weight of the displaced water. This upward force partially cancels gravity, so the net downward pull — the apparent weight — is less than the actual weight in air.
A negative result means the buoyant force exceeds the actual weight, so the object is less dense than the fluid. In practice the object floats — it cannot stay fully submerged without an external downward force.
Volume is derived from mass and density: V = m / ρ_object. If you know the volume directly, use density = mass / volume when entering the object density.
Also known as
TG we-Calculate Editorial Team. (2026). Immersed Weight Calculator — Apparent Weight in Fluid [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/immersed-weight-calculator
TG we-Calculate Editorial Team. "Immersed Weight Calculator — Apparent Weight in Fluid." TG we-Calculate. 2026. https://we-calculate.com/calculator/immersed-weight-calculator.
TG we-Calculate Editorial Team, "Immersed Weight Calculator — Apparent Weight in Fluid," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/immersed-weight-calculator
@misc{wecalculate_immersed_weight_calculator, title = {Immersed Weight Calculator — Apparent Weight in Fluid}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/immersed-weight-calculator}}, year = {2026}, note = {TG we-Calculate} }
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