Select material and shape to calculate linear weight and costs.
Steel (Mild)
Stainless Steel (304/316)
Aluminum (6061)
Brass
Copper
Lead
Titanium
Custom Density
Standard densities in lbs/in³
Please enter a valid positive density.
Round Bar / Rod
Square Bar
Flat Bar / Plate / Sheet
Hexagonal Bar
Round Pipe / Tube
Outer diameter for rods or pipes
Side length or width across flats
Wall thickness must be less than half of diameter.
Length of the piece for total weight calculation
Optional: Enter current market price per pound
Weight Per Linear Foot
2.67 lbs/ft
Total Weight26.70 lbs
Cross-Section Area0.79 in²
Total Material Cost$22.70
Formula Used: Weight = Area (in²) × Density (lbs/in³) × 12
Figure 1: Weight Accumulation over Length vs. Comparison Material
Metric
Value
Unit
Table 1: Detailed breakdown of physical properties and cost.
A Comprehensive Guide to Calculate Weight Per Linear Foot
What is "Calculate Weight Per Linear Foot"?
To calculate weight per linear foot is a fundamental process in engineering, construction, and logistics. It refers to determining the mass of a structural member—such as a steel beam, pipe, or lumber—for every twelve inches of length. This metric is crucial because materials are often priced by weight but sold by length.
Engineers, fabricators, and estimators use this calculation to estimate shipping loads, determine crane requirements, and budget for material costs. Unlike simple weight measurements, knowing the weight per linear foot allows professionals to quickly scale calculations for projects involving thousands of feet of material.
Common Misconceptions: A frequent error is assuming that nominal dimensions match actual dimensions. For example, a "2×4" piece of lumber does not measure 2 inches by 4 inches. Similarly, pipe schedules affect wall thickness, drastically changing the weight per linear foot compared to the outer diameter alone.
Weight Per Linear Foot Formula and Math
The core mathematics behind this calculation relies on volume and density. Since we are calculating "per foot," we take a 1-foot long slice of the object.
The General Formula:
W = A × D × 12
Where:
W = Weight per linear foot (lbs/ft)
A = Cross-Sectional Area (square inches, in²)
D = Material Density (pounds per cubic inch, lbs/in³)
12 = Conversion factor from inches to feet (since density is usually in inches)
Variables Table
Variable
Meaning
Typical Unit
Common Range (Steel)
Density (D)
Mass per unit volume
lbs/in³
0.283 – 0.290
Area (A)
2D Face Area
in²
0.1 – 100+
Length (L)
Total run of material
ft
10ft – 40ft (Stock)
Practical Examples
Example 1: Steel Round Bar
An engineer needs to calculate weight per linear foot for a 2-inch diameter solid steel rod.
Select Material: Choose from common metals like Steel, Aluminum, or enter a custom density. This sets the base weight multiplier.
Choose Shape: Select the profile that matches your material (Round, Square, Plate, etc.). The input fields will adjust automatically.
Enter Dimensions: Input accurate measurements in inches. For pipes, ensure the wall thickness is not greater than the radius.
Set Length & Cost: Enter the total feet required and the cost per pound to see total project estimates.
Analyze Results: Use the "Copy Results" button to save the data for your purchase orders or engineering documents.
Key Factors Affecting Results
When you set out to calculate weight per linear foot, several external factors can influence the final accuracy and financial outcome:
Manufacturing Tolerances: ASTM standards allow for slight variations in thickness and diameter. A "1-inch" plate might be 0.98″ or 1.02″, affecting total weight by ±2-5%.
Material Density Variations: "Steel" is a broad term. Stainless steel (0.29 lbs/in³) is heavier than mild steel (0.283 lbs/in³). Using the wrong density constant can lead to significant estimation errors on large orders.
Corner Radius: Square and rectangular tubing often have rounded corners. Simple calculations assume sharp corners, which slightly overestimates weight. Advanced calculations subtract the missing corner mass.
Coating Weight: Galvanization or heavy painting adds weight. For galvanized steel, add approximately 3-5% to the bare metal weight.
Scrap Factor: When buying by linear foot, you often pay for standard lengths (e.g., 20ft bars). If you need 18ft, you pay for the weight of 20ft.
Cost Fluctuations: Metal markets are volatile. The "Cost per lb" input is critical for financial planning, but prices change daily based on global supply chains.
Frequently Asked Questions (FAQ)
What is the standard weight of steel per foot?
There is no single "standard" weight; it depends entirely on dimensions. However, a common rule of thumb for steel plate is 40.8 lbs per square foot per inch of thickness.
Does the shape affect the weight per linear foot if the area is the same?
No. If a round bar and a square bar have the exact same cross-sectional area (in²), they will weigh the same per linear foot, assuming the material is identical.
Why is my calculation different from the supplier's chart?
Supplier charts often account for corner radii in tubes or standard milling tolerances, whereas theoretical calculations use exact geometric shapes. Suppliers may also round up for billing.
How do I calculate weight for hollow pipes?
Subtract the volume of the inner "air" cylinder from the outer material cylinder. Using the formula: Area = π × (R_outer² – R_inner²).
Can I calculate weight for plastic or wood?
Yes, but you must change the density. Hardwoods typically range from 0.02 to 0.03 lbs/in³, significantly lighter than metals.
Is weight per linear foot the same as linear density?
Yes, in engineering contexts, these terms are often used interchangeably to describe mass distribution along a line.
How accurate is the 0.2833 density for steel?
It is the industry standard for mild carbon steel. However, for high-precision aerospace applications, specific alloy densities should be used.
Does temperature affect the weight calculation?
Technically, thermal expansion changes volume, but mass remains constant. Therefore, the total weight of the beam does not change with temperature, though its length might increase slightly.
Related Tools and Resources
Metal Weight Calculator – A broader tool for calculating weights of various metal shapes and quantities.
Pipe Schedule Chart – Reference standard pipe dimensions and wall thicknesses for accurate inputs.