Size to Weight Calculator (Rectangular Box)

To find the weight of a box without a scale, you can use the relationship between mass and volume: mass = density × volume. Start by measuring the dimensions of the box. Find the box's volume by multiplying together the lengths of the three sides. Estimate or find the density of the material of interest. Make sure that the units agree (for example, use cubic meters for the volume and kilograms per cubic meter for the density), and calculate the mass using: mass = density × volume.

The cube weighs approximately 504 kg. To find this result: Calculate the volume of the cube: V = l × l × l = 0.4 × 0.4 × 0.4 = 0.064 m³ Identify the density of iron: d = 7874 kg/m³. Find the mass using: mass = density × volume = 7874 kg/m³ × 0.064 m³ = 503.94 kg A cube with a side of 40 cm of iron weighs more than half a ton!

To convert from volume to weight, you need to know the density of the material you're working with. The density is a measure of the mass of a known volume: the higher the density, the higher the weight of an object of fixed size. You can find the density of many materials online or measure it yourself from a sample.

Yes, weight and size are proportional — at least if you consider the same material. The constant of proportionality is known as density, a property of matter that characterizes the weight of a given volume.