C12x20.7 is an American Standard steel channel (C shape) that is 12 in deep with a 2.94 in flange and weighs 20.7 lb/ft (30.8 kg/m). Its metric designation is C310x30.8. All values below come from the AISC Shapes Database v16.0.
C12x20.7 Channel Dimensions
| Property | Symbol | Imperial | Metric |
|---|---|---|---|
| Nominal weight | W | 20.7 lb/ft | 30.8 kg/m |
| Cross-sectional area | A | 6.08 inยฒ | 3,920 mmยฒ |
| Depth | d | 12 in | 305 mm |
| Flange width | bf | 2.94 in | 74.7 mm |
| Web thickness | tw | 0.282 in | 7.16 mm |
| Average flange thickness | tf | 0.501 in | 12.7 mm |
| Distance to web toe of fillet (design) | kdes | 1.13 in | 28.7 mm |
| Distance to web toe of fillet (detailing) | kdet | 1.125 in | 28.6 mm |
| Distance between web toes of fillets | T | 9.75 in | 248 mm |
| Workable gage | WGi | 1.75 in | 44.5 mm |
| Centroid distance from back of web | xฬ | 0.698 in | 17.7 mm |
| Shear center distance from web centerline | eo | 0.87 in | 22.1 mm |
C12x20.7 Section Properties
| Property | Symbol | Imperial | Metric |
|---|---|---|---|
| Moment of inertia, x-axis | Ix | 129 inโด | 53.7 ร10โถ mmโด |
| Elastic section modulus, x-axis | Sx | 21.5 inยณ | 352 ร10ยณ mmยณ |
| Plastic section modulus, x-axis | Zx | 25.6 inยณ | 420 ร10ยณ mmยณ |
| Radius of gyration, x-axis | rx | 4.61 in | 117 mm |
| Moment of inertia, y-axis | Iy | 3.86 inโด | 1.61 ร10โถ mmโด |
| Elastic section modulus, y-axis | Sy | 1.72 inยณ | 28.2 ร10ยณ mmยณ |
| Plastic section modulus, y-axis | Zy | 3.47 inยณ | 56.9 ร10ยณ mmยณ |
| Radius of gyration, y-axis | ry | 0.797 in | 20.2 mm |
| Torsional constant | J | 0.369 inโด | 154 ร10ยณ mmโด |
| Warping constant | Cw | 112 inโถ | 30.1 ร10โน mmโถ |
| Polar radius of gyration about shear center | rฬo | 4.93 in | 125 mm |
C12x20.7 Channel Weight Calculator
Enter a length to get the total weight of a C12x20.7 channel. A 20 ft length weighs 414 lb.
Uses the AISC nominal weight: 20.7 lb/ft (30.8 kg/m).
Channels Similar to C12x20.7
Other AISC channels with a nominal depth of 12 in:
| Shape | Weight (lb/ft) | Depth (in) | Flange width (in) | Web (in) |
|---|---|---|---|---|
| C12x25 | 25 | 12 | 3.05 | 0.387 |
| C12x30 | 30 | 12 | 3.17 | 0.51 |
| MC12x10.6 | 10.6 | 12 | 1.5 | 0.19 |
| MC12x14.3 | 14.3 | 12 | 2.12 | 0.25 |
| MC12x31 | 31 | 12 | 3.67 | 0.37 |
| MC12x35 | 35 | 12 | 3.77 | 0.465 |
| MC12x40 | 40 | 12 | 3.89 | 0.59 |
| MC12x45 | 45 | 12 | 4.01 | 0.71 |
| MC12x50 | 50 | 12 | 4.14 | 0.835 |
See every standard channel in the C-channel sizes chart, or the MC channel dimensions chart for miscellaneous channels.
C12x20.7 Channel FAQ
What does C12x20.7 mean?
C means American Standard channel. The first number (12) is the nominal depth in inches, and the second number (20.7) is the weight in pounds per foot. The actual depth of C12x20.7 is 12 in.
How much does a C12x20.7 channel weigh?
C12x20.7 weighs 20.7 lb per foot (30.8 kg per meter). A 20 ft length weighs about 414 lb.
What is the metric equivalent of C12x20.7?
The metric (SI) designation is C310x30.8: 305 mm deep with a 74.7 mm flange and 30.8 kg/m.
Where is the centroid of a C12x20.7 channel?
A channel is not symmetric about its vertical axis. The centroid of C12x20.7 sits 0.698 in (17.7 mm) from the back of the web, and the shear center is 0.87 in from the web centerline, on the side away from the flanges.
What size load can a C12x20.7 channel carry?
Capacity depends on the span, load, bracing, connections and local building code, so it cannot be read from a size table. A licensed structural engineer must size any channel that carries a load.
Source: AISC Shapes Database v16.0, consistent with the AISC Steel Construction Manual, 16th Edition. Last updated: September 2026.
This page is reference information only and is not engineering advice. Do not use it for a specific design without verification by a licensed engineer or architect. Full disclaimer.