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Structural · W — wide-flange

W8x18 Steel Beam — Dimensions & Properties

W8x18 weighs 18 lb/ft and is about 8.14 in deep. Below: the full AISC section properties, a scaled cross-section, and a pre-filled weight calculator.

Weight
18lb/ft
Depth
8.14in
Width
5.25in
Area
5.26in²
Shape
W8X18 · 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 × W8X18
360lb
Per piece
360lb
Pieces
1
Total
360lb
Tons
0.18t
d8.14"bf 5.25"tw 0.23
ƒShow the math
  1. 1.Weight per foot (from AISC)per AISC Shapes Database v16.0

    W8X18 is a listed shape; its nominal weight is a published property.

    = 18 lb/ft
  2. 2.Length in feet
    length (in) ÷ 12
    240 ÷ 12
    = 20 ft
  3. 3.Weight per piece
    weight per foot × length
    18 × 20
    = 360 lb
  4. 4.Total weight
    weight per piece × quantity
    360 × 1
    = 360 lb
  5. 5.Convert to tons
    total lb ÷ 2000
    360 ÷ 2000
    = 0.18 tons

Section properties

Geometry
Weight
18lb/ft
Area, A
5.26in²
Depth, d
8.14in
Flange width, bf
5.25in
Flange thick, tf
0.33in
Web thick, tw
0.23in
Strong axis (x-x)
Ix
61.9in⁴
Sx
15.2in³
Zx
17in³
rx
3.43in
Weak axis (y-y)
Iy
7.97in⁴
Sy
3.04in³
Zy
4.66in³
ry
1.23in
Torsion & warping
J
0.172in⁴
Cw
122in⁶
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.

W8x10 10 lb/ftW8x13 13 lb/ftW8x24 24 lb/ftW8x31 31 lb/ftW8x40 40 lb/ftW8x48 48 lb/ftW8x67 67 lb/ftW10x33 33 lb/ftW10x12 12 lb/ftW10x49 49 lb/ft

W8x18 — questions

How much does a W8x18 weigh per foot?
A W8x18 weighs 18 lb/ft. Over a 20-foot length that is 360 lb (0.18 tons); a 30-foot length is 540 lb.
What are the dimensions of a W8x18?
W8x18 has an actual depth of 8.14 in and a flange width of 5.25 in, a flange thickness of 0.33 in, and a web thickness of 0.23 in. Cross-sectional area is 5.26 in².
What is the moment of inertia and section modulus of a W8x18?
About its strong axis, W8x18 has a moment of inertia Ix of 61.9 in⁴ and a section modulus Sx of 15.2 in³, with a plastic section modulus Zx of 17 in³. Use these with your engineer's design values — they are geometric properties, not an allowable load.
What does W8x18 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 W8x18 is a nominally 8-inch-deep wide-flange beam weighing 18 lb/ft (actual depth 8.14 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.