CNC / machinist calculator
Metal Weight Calculator
Work out what a piece of stock weighs before you order it, lift it, or quote it. Pick the shape, round, rectangular or hex bar, tube, or plate, choose the metal, and enter the dimensions and length. The calculator returns the weight in pounds and kilograms using standard densities for common engineering metals. It is the quick check for shipping, work-holding and material cost.
How it works
Weight is volume times density. The volume comes from the stock shape: a round bar is its cross-section area, pi over four times the diameter squared, times the length; a rectangular bar is width times thickness times length; a tube is the area of the outer circle minus the inner circle, times the length; a hexagon across the flats has an area of the square root of three over two times the flat dimension squared.
Density is the property of the metal. Steel is about 0.284 pounds per cubic inch, stainless a little more, aluminum roughly a third of steel, and titanium between them. The calculator multiplies the shape volume by the selected metal's density to get the weight, and converts to kilograms for metric ordering.
These densities are nominal values for the base metal. Specific alloys vary slightly, and extruded or cast tolerances change the real cross-section, so treat the result as an accurate estimate for planning rather than a certified mass.
Worked example
A 12 in length of 1 in round steel bar: area pi/4 x 1^2 times 12 in times 0.284 lb/in^3 = 2.68 lb.
Frequently asked questions
How do I calculate the weight of a metal bar?
Multiply the cross-section area by the length to get the volume, then multiply by the metal's density. For a round bar the area is pi over four times the diameter squared, so weight is that area times length times density.
What is the density of steel?
Carbon steel is about 0.284 pounds per cubic inch, or roughly 7.85 grams per cubic centimetre. Stainless is slightly higher at about 0.289, and cast iron a bit lower around 0.26 pounds per cubic inch.
How much lighter is aluminum than steel?
Aluminum is about 0.098 pounds per cubic inch against steel's 0.284, so it is roughly one third the weight for the same volume. Titanium sits between them at about 0.163 pounds per cubic inch.
How do I find the weight of tube or pipe?
Use the tube area, which is pi over four times the outer diameter squared minus the inner diameter squared, then multiply by length and density. The calculator does this when you enter the outer and inner diameters.
Are these weights exact?
They use nominal base-metal densities, so they are accurate for planning and quoting but not certified. Specific alloys vary slightly and stock tolerances change the real cross-section, which shifts the actual weight a little.
Related calculators
Sources
- Densities of metals and elements (Engineering ToolBox)
- Density of common metals (Wikipedia, list of densities)
Every formula on this page is shown and sourced. See how we verify.
These calculators are for planning and as a starting point. Recommended speeds and feeds are published starting values that vary with your specific tool, coating, machine rigidity, workholding and coolant. Always start conservative, listen to the cut, and follow your tool maker data sheet.