S12X31.8 Dimensions & Weight
S12X31.8 is an AISC American Standard (S) beam with an actual depth of 12 in and a 5 in flange, weighing 31.8 lb per foot — commonly used for light floor framing, mezzanines, and residential beams. It is the lightest of the 4 S12 sizes listed here.
S12X31.8 Dimensions
| Property | Imperial | Metric |
|---|---|---|
| Depth (d) | 12 in | 304.8 mm |
| Flange width (bf) | 5 in | 127 mm |
| Cross-section area (A) | 9.35 in² | 60.3 cm² |
| Weight | 31.8 lb/ft | 47.3 kg/m |
Standard: AISC. Values from the published section tables; dimensions not listed here are not shown rather than estimated.
What does S12X31.8 weigh and cost?
S12X31.8 weighs 31.8 lb per foot. At an example material price of $0.92/lb that is about $29.26 per foot. Set your quantity, length, and price to total your own run:
Material only, example pricing. Actual steel pricing varies by region, grade, quantity, and market conditions — use your own supplier numbers for real bids.
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Related sizes
Deeper reading: AISC Shape Database Guide · How to calculate steel weight