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Structural · W — wide-flange

W12x40 Steel Beam — Dimensions & Properties

W12x40 weighs 40 lb/ft and is about 11.94 in deep. Below: the full AISC section properties, a scaled cross-section, and a pre-filled weight calculator.

Weight
40lb/ft
Depth
11.94in
Width
8.005in
Area
11.7in²
Shape
W12X40 · W — wide-flange

Enter feet + inches, e.g. 20' or 18' 6".

= 20' (240″)
pcs
Cost estimate (optional)
$/lb

Optional. Prices are volatile — use your current mill/supplier rate.

Total weight
1 × W12X40
800lb
Per piece
800lb
Pieces
1
Total
800lb
Tons
0.4t
d11.94"bf 8.005"tw 0.295
ƒShow the math
  1. 1.Weight per foot (from AISC)per AISC Shapes Database v16.0

    W12X40 is a listed shape; its nominal weight is a published property.

    = 40 lb/ft
  2. 2.Length in feet
    length (in) ÷ 12
    240 ÷ 12
    = 20 ft
  3. 3.Weight per piece
    weight per foot × length
    40 × 20
    = 800 lb
  4. 4.Total weight
    weight per piece × quantity
    800 × 1
    = 800 lb
  5. 5.Convert to tons
    total lb ÷ 2000
    800 ÷ 2000
    = 0.4 tons

Section properties

Geometry
Weight
40lb/ft
Area, A
11.7in²
Depth, d
11.94in
Flange width, bf
8.005in
Flange thick, tf
0.515in
Web thick, tw
0.295in
Strong axis (x-x)
Ix
307in⁴
Sx
51.5in³
Zx
57in³
rx
5.13in
Weak axis (y-y)
Iy
44.1in⁴
Sy
11in³
Zy
16.8in³
ry
1.94in
Torsion & warping
J
0.906in⁴
Cw
1,440in⁶
Before you rely on this
  • Listed weight is the AISC theoretical (nominal) weight per foot. Actual mill weight varies within ASTM rolling tolerance, roughly ±2.5%.
  • This is bare member steel only. Add plates, stiffeners, connections, bolts, and coatings for a full erected-steel takeoff.

Similar shapes

Same series and nearest depths — compare weight and section modulus when you are sizing.

W12x14 14 lb/ftW12x16 16 lb/ftW12x19 19 lb/ftW12x22 22 lb/ftW12x26 26 lb/ftW12x30 30 lb/ftW12x50 50 lb/ftW12x65 65 lb/ftW12x87 87 lb/ftW12x106 106 lb/ft

W12x40 — questions

How much does a W12x40 weigh per foot?
A W12x40 weighs 40 lb/ft. Over a 20-foot length that is 800 lb (0.4 tons); a 30-foot length is 1,200 lb.
What are the dimensions of a W12x40?
W12x40 has an actual depth of 11.94 in and a flange width of 8.005 in, a flange thickness of 0.515 in, and a web thickness of 0.295 in. Cross-sectional area is 11.7 in².
What is the moment of inertia and section modulus of a W12x40?
About its strong axis, W12x40 has a moment of inertia Ix of 307 in⁴ and a section modulus Sx of 51.5 in³, with a plastic section modulus Zx of 57 in³. Use these with your engineer's design values — they are geometric properties, not an allowable load.
What does W12x40 mean?
The W means wide-flange. The first number is the nominal depth in inches and the second is the weight in pounds per foot — so W12x40 is a nominally 12-inch-deep wide-flange beam weighing 40 lb/ft (actual depth 11.94 in).

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Sources & references

Estimates for planning purposes only. Verify all results against the code edition adopted in your jurisdiction and with your Authority Having Jurisdiction (AHJ). This tool is not a substitute for a licensed professional engineer. See our methodology, sources, and code editions.

Data: AISC Shapes Database v16.0, © AISC — used per its developer-use provision.