Material Weight Calculator
Pick the stock shape —bar, plate or tube—, enter its dimensions and get the weight instantly in over 80 metals and plastics. The shape is drawn in 3D as you type.
Prefer PREMSAWeight from dimensions, no file
Round bar
Stock shape
Dimensions
Materials
Density
0.0975 lb/in³
Material weight
3.67731lb
Weight per piece
3.67731 lb
Cross-section area
3.1416 in²
Volume per piece
37.699 in³
This is the theoretical weight with sharp corners: the corner radii of a square tube change it by less than 1%. Actual weight also varies with mill tolerance and the density of the exact grade.
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How it works
The weight of stock with a constant cross-section is its section area times its length times the density. The calculator gets the area from each shape's formula —a circle, square, rectangle, hexagon or tube— using the dimensions you enter, then multiplies it by the length and by the density of the material you pick.
How to use the calculator
- 1
Pick the shape: round, square, rectangular or hex bar, plate or flat bar, or round, square or rectangular tube.
- 2
Enter the dimensions in millimeters or inches. The shape is redrawn in 3D with each value, so you can see right away whether you entered what you meant.
- 3
Pick the material. “PREMSA” lists the materials we machine, “All materials” has the rest, and in “Custom” you enter the density from your certificate.
- 4
If you need several identical pieces, enter the quantity: the large number is the total and the weight of each piece is shown below.
Worked example
Aluminum round bar
- Inputs
- Round bar, Ø50 mm and 300 mm long, in 6061-T6 aluminum (2,700 kg/m³).
- Result
- Volume = 589.05 cm³ and weight = 1.590 kg (3.506 lb).
- Area = π × 50² ÷ 4 = 1,963.5 mm². Volume = 1,963.5 mm² × 300 mm = 589,049 mm³ = 589.05 cm³. 589.05 cm³ × 2.70 g/cm³ = 1,590.4 g.
Formula
m = A × L × ρ
A is the cross-section area (π·d²/4 for a round bar; π/4·(D² − (D − 2t)²) for a tube; a·h for a rectangular bar), L is the length and ρ the material density.
Assumptions and limits
- The cross-section is the same along the whole length.
- Corners are sharp: the corner radii of tubes and square bars are not counted, and change the weight by less than 1%.
- Densities are nominal values for each alloy or resin. If you have the material certificate, use “Custom”.
Where the densities come from
Each density comes from the body that defines the alloy or the company that makes the resin, at 20 °C: the Aluminum Association, the ASM Handbook, the Copper Development Association and each plastic maker's datasheet.
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Questions about material weight
- How do you calculate the weight of a round bar?
- Multiply the circle's area (π × diameter² ÷ 4) by the length and the density. A 1 in steel bar 12 in long weighs 0.7854 in² × 12 in × 0.2836 lb/in³ = 2.67 lb.
- How do you calculate the weight of a plate or flat bar?
- Width × thickness × length × density. A 6061 aluminum plate 8 × 0.5 × 12 in is 48 in³ and weighs 4.68 lb.
- How do you calculate the weight of a tube?
- Subtract the inner circle from the outer one: π ÷ 4 × (D² − (D − 2t)²), where D is the outside diameter and t the wall thickness. Then multiply by the length and the density.
- Is hex bar measured across flats or across corners?
- Across flats, which is how it is sold and measured with calipers. The area of a hexagon is √3 ÷ 2 × (across flats)².
- How accurate is the weight?
- The math is exact for the dimensions you enter. The difference from a scale comes from mill tolerance, corner radii and the actual density of the grade, and is usually 1 to 3%.
- Can I calculate the weight of several pieces?
- Yes. Enter the quantity: the large number is the total weight and the weight of one piece is shown below.
- What if my material isn't listed?
- Look in “All materials” first. If it isn't there, choose “Custom” and enter its density in kg/m³, g/cm³ or lb/in³; you'll find it on the supplier's datasheet or the material certificate.
- How is this different from the part weight calculator?
- This one weighs raw STOCK from its dimensions. The part weight calculator reads your STEP file and weighs the finished part, with its holes, pockets and cutouts already removed.
Multiply the circle's area (π × diameter² ÷ 4) by the length and the density. A 1 in steel bar 12 in long weighs 0.7854 in² × 12 in × 0.2836 lb/in³ = 2.67 lb.
Width × thickness × length × density. A 6061 aluminum plate 8 × 0.5 × 12 in is 48 in³ and weighs 4.68 lb.
Subtract the inner circle from the outer one: π ÷ 4 × (D² − (D − 2t)²), where D is the outside diameter and t the wall thickness. Then multiply by the length and the density.
Across flats, which is how it is sold and measured with calipers. The area of a hexagon is √3 ÷ 2 × (across flats)².
The math is exact for the dimensions you enter. The difference from a scale comes from mill tolerance, corner radii and the actual density of the grade, and is usually 1 to 3%.
Yes. Enter the quantity: the large number is the total weight and the weight of one piece is shown below.
Look in “All materials” first. If it isn't there, choose “Custom” and enter its density in kg/m³, g/cm³ or lb/in³; you'll find it on the supplier's datasheet or the material certificate.
This one weighs raw STOCK from its dimensions. The part weight calculator reads your STEP file and weighs the finished part, with its holes, pockets and cutouts already removed.
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