Calculate Steel Weight for 30 Metals: Formula & Calculator

I. Weight Calculation Formula

(1) Density-Based Formula

The following weight calculation formula can be used to calculate the steel/metal weight:

Weight (kg) = Sectional Area (mm²) × Length (m) × Density (ρ, g/cm³)× 1/1000

Above is the formula to calculate the steel weight in kg.

Determination of Density

For the metal density, you can also refer to the following:

• Density Table of Metals (Iron, Steel, Brass, Aluminum) and Alloys
• Density Table for Commonly Used Sheet Metal Materials

II. Steel & Metal Weight Calculator

To assist you in calculating the weight of various metals and steels, including MS plate, GI sheet, structural steel, MS angle, mild steel, steel bar, square tube, angle, and aluminum, we have created a Steel Weight Calculator and Metal Weight Calculator to help you determine the weight of metals in different shapes.

III. Metal & Steel Weight Calculation Formula

The unit of measurement for calculating the theoretical weight of steel is kilograms (kg). The basic formula is:

W (Weight, kg) = F (Cross-sectional Area, mm²) × L (Length, m) × ρ (Density, g/cm³) × 1/1000

The density of steel is: 7.85g/cm³

Simple Steel Weight Calculation Formulas

Simply enter data indicated (Decimal Inches), move from left to right making computations by factors as shown.

• ROUND Diameter x Diameter x 2.6729 = Lbs. Per Foot 
• FLAT Thickness x Width x 3.4032 = Lbs. Per Foot 
• SQUARE Diameter x Diameter x 3.4032 = Lbs. Per Foot 
• HEXAGON *Diameter x Diameter x 2.9437 = Lbs. Per Foot 
• OCTAGON *Diameter x Diameter x 2.8193 = Lbs. Per Foot 
• PIPE Actual O.D. – Wall x Wall x 10.68 = Lbs. Per Foot
• TUBE O.D. – Wall  x Wall  x 10.68 = Lbs. Per Foot  
• SHEET Thickness  x Width  x  Length  x  .2904 = Lbs. Each
• COIL O.D. x O.D.  – I.D.  x I.D. x .2223 = Lbs. Per Inch of Width 
• SHEET CIRCLE Diameter x  Diameter x  Thickness x  .228 = Lbs. Each
• PLATE Thickness  x  Width  x  Length x  .2836 = Lbs. Each

PLATE SHAPES:

• CIRCLE Diameter x  Diameter x  Thickness  x  .2227 = Lbs. Each
• RING Diameter x Diameter – I.D. x I.D. x Thickness x .2227 = Lbs. Each
• CIRCLE SECTOR    Radius x Radius x Number of Degrees in Arc x Thickness  x  .0025 = Lbs. Each
• TRIANGLE (Right Angle) Base Length  x  Height  x Thickness  x  .1418 = Lbs. Each
• TRAPEZOIDS (2 Sides Parallel) Side “A”  + Side “B”  x Height x Thickness  x 14.18 = Lbs.Each
• HEXAGON (Equal Sides) Side Length  x  Side Length x  .7367 = Lbs. Each
• OCTAGON Side Length  x  Side Length  x  1.3692 = Lbs. Each

NOTE: Formulas Are Based on Nominal Weights at .2836 Lbs. Per Cubic Inch and Should Be Considered Approximations Only Rather Than Actual Scale Weight

Weights of Various Metals in Pounds Per *Cubic Foot

1. Steel Plate weight calculation formula

• Formula: length(m)×width(m)×thickness(mm)×7.85
• E.g: 6m (length)×1.51m(width)×9.75mm (thickness)
• Calculation: 6×1.51×9.75×7.85=693.43kg

2. Steel Pipe weight calculation formula

• Formula: (OD-wall thickness)×wall thickness(mm)×length(m)×0.02466
• E.g: 114mm(OD)×4mm(wall thickness)×6m(length)
• Calculation: (114-4)×4×6×0.02466=65.102kg

3. Steel Rod weight calculation formula

• Formula: dia.(mm)×dia.(mm)×length(m)×0.00617
• E.g: Φ20mm (dia.)×6m(length)
• Calculation: 20×20×6×0.00617=14.808kg

4. Square Steel weight calculation formula

• Formula: side width(mm)×side width(mm)×length(m)×0.00785
• E.g: 50mm(side width)×6m(length)
• Calculation: 50×50×6×0.00785=117.75(kg)

5. Flat Steel weight calculation formula

• Formula: side width(mm)×thickness(mm)×length(m)×0.00785
• E.g: 50mm(side width)×5.0mm(thickness)×6m(length)
• Calculation: 50×5×6×0.00785=11.775(kg)

6. Hexagonal Steel weight calculation formula

• Formula: side-to-side dia.×side-to-side dia.× length(m)×0.0068
• E.g: 50mm(dia.)×6m (length)
• Calculation: 50×50×6×0.0068=102(kg)

7. Rebar weight calculation formula

• Formula: dia.mm×dia.mm×length(m)×0.00617
• E.g: Φ20mm(dia.)×12m(length)
• Calculation: 20×20×12×0.00617=29.616kg

8. Flat Steel Tube weight calculation formula

• Formula: (side length+side width)×2×thickness×length(m)×0.00785
• E.g: 100mm×50mm×5mm(thickness)×6m (length)
• Calculation: (100+50)×2×5×6×0.00785=70.65kg

9. Rectangular Steel Tube weight calculation formula

• Formula: side width(mm)×4×thickness×length(m)×0.00785
• E.g: 50mm×5mm (thickness)×6m(length)
• Calculation: 50×4×5×6×0.00785=47.1kg

10. Equal-leg Angle Steel weight calculation formula

• Formula: (side width×2-thickness)×thickness×length(m)×0.00785
• E.g: 50mm×50mm×5(thickness)×6m(length)
• Calculation: (50×2-5)×5×6×0.00785=22.37kg

11. Unequal-leg Angle Steel weight calculation formula

• Formula: (side width+side width-thickness)×thickness×length(m)×0.0076
• E.g: 100mm×80mm×8(thickness)×6m(length)
• Calculation: (100+80-8)×8×6×0.0076=62.746kg

12. Brass Pipe weight calculation formula

• Formula: (OD-wall thickness)×thickness(mm)×length(m)×0.0267

13. Copper Pipe weight calculation formula

• Formula: (OD-wall thickness)×thickness(mm)×length(m)×0.02796

14. Aluminum Checkered Sheet weight calculation formula

• Formula: length(m)×width(mm)×thickness (mm)×0.00296

15. Brass Pipe weight calculation formula

• Formula: length(m)×width(mm)×thickness(mm)×0.0085

16. Copper Sheet weight calculation formula

• Formula: length(m)×width(mm)×thickness(mm)×0.0089

17. Zinc Plate weight calculation formula

• Formula: length(m)×width(mm)×thickness(mm)×0.0072

18. Lead Sheet weight calculation formula

• Formula: length(m)×width(mm)×thickness(mm)×0.01137

19. Octagonal Steel weight calculation formula

• Formula: length(m)×across width(mm)×across width(mm)×0.0065

20. Copper Rod weight calculation formula

• Formula: dia.(mm)×dia.(mm)×length(m)×0.00698

21. Brass Rod weight calculation formula

• Formula: dia.(mm)×dia.(mm)×length(m)×0.00668

22. Aluminum Rod weight calculation formula

• Formula: dia.(mm)×dia.(mm)×length(m)×0.0022

23. Square Copper Rod weight calculation formula

• Formula: width(mm)×width(mm)×length(m)×0.0089

24. Square Brass Rod weight calculation formula

• Formula: width(mm)×width(mm)×length(m)×0.0085

25. Square Aluminum Rod weight calculation formula

• Formula: width(mm)×width(mm)×length(m)×0.0028

26. Hexagonal Copper Rod weight calculation formula

• Formula: across width(mm)×across width(mm)×length(m)×0.0077

27. Hexagonal Brass Rod weight calculation formula

• Formula: width(mm)×across width(mm)×length(m)×0.00736

28. Hexagonal Aluminum Rod weight calculation formula

• Formula: across width(mm)×across width(mm)×length(m)×0.00242

29. Aluminum Plate weight calculation formula

• Formula: thickness(mm)×width(mm)×length(m)×0.00171

30. Aluminum Pipe weight calculation formula

• Formula: thickness(mm)×(O.D(mm)-thickness(mm))×length(m)×0.00879

Common sources of error in the calculation of metal material weight

Accurate weight calculation of metal materials is crucial for various industrial applications, yet several factors can introduce errors. Understanding these sources is essential for precise engineering and cost estimation. The following are key points to consider:

Density Variations: The accuracy of material density is paramount in weight calculations. Density can vary due to alloy composition, manufacturing processes, and even within the same batch of materials. For instance, the density of steel can range from 7.75 to 8.05 g/cm³ depending on its carbon content and alloying elements. Using a generic density value instead of the specific grade’s density can lead to significant errors, especially in large-scale projects.

Dimensional Tolerances: Manufacturing processes inherently produce components with dimensional variations within specified tolerances. These deviations from nominal dimensions directly impact weight calculations. For example:

• Seamless steel pipes typically have tolerances of ±1% on outside diameter and ±12.5% on wall thickness for standard grades.
• Hot-rolled structural steel I-beams often have a permissible weight tolerance of +2.5% to -2.5% according to ASTM A6/A6M standards.

Thermal Expansion Effects: Temperature fluctuations can significantly affect material dimensions and, consequently, weight measurements. The linear thermal expansion coefficient (α) varies among metals:

• Aluminum: α ≈ 23.1 × 10⁻⁶ /°C
• Steel: α ≈ 11.7 × 10⁻⁶ /°C
• Copper: α ≈ 16.6 × 10⁻⁶ /°C
  These differences become critical when calculating weights for high-temperature applications or when precise measurements are taken in varying environmental conditions.

Theoretical vs. Actual Weight Discrepancies: Even under ideal conditions, theoretical weight calculations may deviate from actual weights due to factors such as:

• Surface roughness and finish
• Internal microstructure variations
• Presence of residual stresses
• Minor impurities or inclusions
  Typically, the discrepancy between theoretical and actual weights falls within 0.2% to 0.7% for standard metal products. However, this range can increase for custom or complex geometries.

Material Processing Effects: Various manufacturing processes can alter the material’s weight distribution:

• Welding can add filler material weight
• Machining operations remove material
• Surface treatments like galvanization or anodizing add thin layers of material

These factors, often overlooked in theoretical calculations, can contribute to weight discrepancies, especially in fabricated assemblies.

By accounting for these potential sources of error, engineers and manufacturers can improve the accuracy of their weight calculations, leading to more precise material planning, cost estimation, and structural design in metal fabrication projects.