How this calculator works
Subtract buoyancy from true weight to obtain the signed support force needed to hold an immersed object at rest. A negative result means that a downward restraint is required. The density inferred for the object assumes complete immersion and no absorbed liquid or trapped bubbles. For a straight-sided vessel, surface area times liquid-level rise measures displaced volume. A scale calibrated in mass reports support force divided by the calibration gravity; this page uses the entered gravity for both.
Formula
B = rho_fluid g V; W = mg; apparent weight = W - B; apparent mass = m - rho_fluid V. Fully immersed object density = m/V. Displacement from liquid rise: V = A delta h.
Worked example
A 10 kg object displacing 0.002 m3 of water experiences 19.6133 N buoyancy at standard gravity. Its true weight is 98.0665 N and apparent weight is 78.4532 N, equivalent to an 8 kg reading.
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Frequently asked questions
Can apparent weight be negative?
Yes. It represents a downward holding force when buoyancy exceeds the object weight, rather than a reading on an ordinary hanging scale.
Can I infer density from partial immersion?
The result m/V is the true average object density only when V is the entire object volume. Partly immersed displaced volume is smaller.
Do bubbles matter?
Attached bubbles and trapped air add displacement and can bias an immersion density measurement.