How this calculator works
Density times volume gives mass. Multiplying that mass by local gravitational acceleration gives weight as a force, in newtons or pounds-force. This extra gravity step matters when estimating support loads or comparing environments. The rectangular option multiplies three dimensions for a uniform solid block. Reverse modes recover volume or density from a known gravitational force. The default is standard gravity, 9.80665 m/s². This calculation reports gravitational weight; buoyancy, rotation and an accelerating support can change an actual scale reading.
Formula
m = rho V; W = rho V g; V = W/(rho g); rho = W/(Vg); specific weight gamma = rho g. For a rectangular block, V = length x width x height.
Worked example
A 2 L sample at 1000 kg/m³ has mass 2 kg. At g = 10 m/s² it weighs 20 N. The same sample at g = 1.62 m/s² still has mass 2 kg but weighs 3.24 N.
Frequently asked questions
Why is weight not displayed in kilograms?
Kilograms measure mass. This page displays mass separately and uses force units for gravitational weight.
Can I enter pounds?
Use the force input in lbf for a known weight, or a density in lb/ft³. Pounds-force and pounds of mass describe different quantities.
Does this give submerged weight?
No. Subtract displaced-fluid buoyancy to obtain the support force on a submerged object. The immersed weight page performs that calculation.