These calculators do a rough estimate of the weight of blocks and pipes. Input dimensions and the relevant density from the table below. (Though if you know the actual density, feel free to use that instead.)

Rectangular Block Weight Calculator
Length (mm):
Width (mm):
Height (mm):
Density (g/cm^3):
Weight (kg):

Pipe Weight Calculator
Length (mm):
Outer diameter (mm):
Inner diameter (mm):
Density (g/cm^3):
Weight (kg):

The (approximate!) density for a range of metals are given in the table below:

Metal Density (g/cm^3)
Carbon steel 8
Stainless steel 8
Aluminium 2.7
Copper 9
Magnesium 1.7
Nickel 9
Titanium 4.5