W8x10 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W8x10 is an American wide-flange beam 7.89 inches (200.4 mm) deep with a 3.94 in (100.1 mm) flange, weighing 10 pounds per foot (14.9 kg/m) — that is what the "10" in the designation means. All values below are the standard AISC published section properties used in US structural design, with metric equivalents alongside.
Typical uses: floor and roof framing, columns, headers, and general steel construction. For a quick stiffness check, see the deflection example below or open the beam calculator with your own span and load.
W8x10: cross-section drawn to scale from the AISC dimensions (d 7.89, bf 3.94, tw 0.17, tf 0.205 in)Dimensions
| Depth d | 7.89 in (200.4 mm) |
| Flange width bf | 3.94 in (100.1 mm) |
| Web thickness tw | 0.17 in (4.3 mm) |
| Flange thickness tf | 0.205 in (5.2 mm) |
Weight & Cross-Section
| Weight per foot | 10 lb/ft (14.9 kg/m) |
| 20 ft bar | 200 lb |
| 40 ft bar | 400 lb |
| Area A | 2.96 in² (19.1 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 30.8 in⁴ (1,282 cm⁴) |
| Section modulus Sx | 7.81 in³ (128 cm³) |
| Radius of gyration rx | 3.22 in |
| Moment of inertia Iy | 2.09 in⁴ (87 cm⁴) |
| Section modulus Sy | 1.06 in³ (17 cm³) |
| Radius of gyration ry | 0.84 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|
| W8x10 (this page) | 7.89 × 3.94 | 10 | 30.8 | 7.81 | — | — |
| W8x13 | 7.99 × 4 | 13 | 39.6 | 9.91 | +30 % | +29 % |
Deflection example
A simply supported W8x10 spanning 13 ft with a 10 kip point load at midspan deflects 0.89 in (E = 29,000 ksi, Ix = 30.8 in⁴). The L/360 serviceability limit for this span is 0.43 in — the shape does NOT pass this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W8x10 beam weigh?
W8x10 weighs 10 pounds per foot (14.9 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 200 lb and a 40 ft bar 400 lb.
What are the dimensions of a W8x10?
W8x10 is 7.89 in (200.4 mm) deep with a 3.94 in (100.1 mm) wide flange. The web is 0.17 in thick and the flanges are 0.21 in thick. Note the actual depth differs from the nominal W8 label — always design with the actual value.
What are the dimensions of a W8x10 in mm?
W8x10 is 200.4 mm deep with a 100.1 mm wide flange; the web is 4.3 mm and the flange 5.2 mm thick. In metric section properties: Ix = 1,282 cm⁴, Sx = 128 cm³.
How much does a W8x10 weigh in kg?
14.9 kg per meter. A 6 m bar weighs 89 kg and a 12 m bar 179 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W8x10?
About the strong axis, Ix = 30.8 in⁴ (1,282 cm⁴) with section modulus Sx = 7.81 in³. About the weak axis, Iy = 2.09 in⁴ and Sy = 1.06 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W8x10 or W8x13 — what does one size up change?
W8x13 is about 30% heavier (13 vs 10 lb/ft) but about 29% stiffer (Ix 39.6 vs 30.8 in⁴). Going one step up within the same depth group is usually the cheapest way to cut deflection.
Values are entered from the governing standard’s published tables and cross-checked programmatically against its mass and section formulas before publication. Spotted an error? Write to advertising@metalabout.net — verified corrections ship within days. About