C8x18.75 is an American Standard steel channel (C shape) that is 8 in deep with a 2.53 in flange and weighs 18.75 lb/ft (27.9 kg/m). Its metric designation is C200x27.9. All values below come from the AISC Shapes Database v16.0.
C8x18.75 Channel Dimensions
| Property | Symbol | Imperial | Metric |
|---|---|---|---|
| Nominal weight | W | 18.75 lb/ft | 27.9 kg/m |
| Cross-sectional area | A | 5.51 inยฒ | 3,550 mmยฒ |
| Depth | d | 8 in | 203 mm |
| Flange width | bf | 2.53 in | 64.3 mm |
| Web thickness | tw | 0.487 in | 12.4 mm |
| Average flange thickness | tf | 0.39 in | 9.91 mm |
| Distance to web toe of fillet (design) | kdes | 0.938 in | 23.8 mm |
| Distance to web toe of fillet (detailing) | kdet | 0.9375 in | 23.8 mm |
| Distance between web toes of fillets | T | 6.125 in | 156 mm |
| Workable gage | WGi | 1.5 in | 38.1 mm |
| Centroid distance from back of web | xฬ | 0.565 in | 14.4 mm |
| Shear center distance from web centerline | eo | 0.431 in | 10.9 mm |
C8x18.75 Section Properties
| Property | Symbol | Imperial | Metric |
|---|---|---|---|
| Moment of inertia, x-axis | Ix | 43.9 inโด | 18.3 ร10โถ mmโด |
| Elastic section modulus, x-axis | Sx | 11 inยณ | 180 ร10ยณ mmยณ |
| Plastic section modulus, x-axis | Zx | 13.9 inยณ | 228 ร10ยณ mmยณ |
| Radius of gyration, x-axis | rx | 2.82 in | 71.6 mm |
| Moment of inertia, y-axis | Iy | 1.97 inโด | 0.82 ร10โถ mmโด |
| Elastic section modulus, y-axis | Sy | 1.01 inยณ | 16.6 ร10ยณ mmยณ |
| Plastic section modulus, y-axis | Zy | 2.17 inยณ | 35.6 ร10ยณ mmยณ |
| Radius of gyration, y-axis | ry | 0.598 in | 15.2 mm |
| Torsional constant | J | 0.434 inโด | 181 ร10ยณ mmโด |
| Warping constant | Cw | 25.1 inโถ | 6.74 ร10โน mmโถ |
| Polar radius of gyration about shear center | rฬo | 3.05 in | 77.5 mm |
C8x18.75 Channel Weight Calculator
Enter a length to get the total weight of a C8x18.75 channel. A 20 ft length weighs 375 lb.
Uses the AISC nominal weight: 18.75 lb/ft (27.9 kg/m).
Channels Similar to C8x18.75
Other AISC channels with a nominal depth of 8 in:
| Shape | Weight (lb/ft) | Depth (in) | Flange width (in) | Web (in) |
|---|---|---|---|---|
| C8x13.75 | 13.75 | 8 | 2.34 | 0.303 |
| C8x11.5 | 11.5 | 8 | 2.26 | 0.22 |
| MC8x8.5 | 8.5 | 8 | 1.87 | 0.179 |
| MC8x18.7 | 18.7 | 8 | 2.98 | 0.353 |
| MC8x20 | 20 | 8 | 3.03 | 0.4 |
| MC8x21.4 | 21.4 | 8 | 3.45 | 0.375 |
| MC8x22.8 | 22.8 | 8 | 3.5 | 0.427 |
See every standard channel in the C-channel sizes chart, or the MC channel dimensions chart for miscellaneous channels.
C8x18.75 Channel FAQ
What does C8x18.75 mean?
C means American Standard channel. The first number (8) is the nominal depth in inches, and the second number (18.75) is the weight in pounds per foot. The actual depth of C8x18.75 is 8 in.
How much does a C8x18.75 channel weigh?
C8x18.75 weighs 18.75 lb per foot (27.9 kg per meter). A 20 ft length weighs about 375 lb.
What is the metric equivalent of C8x18.75?
The metric (SI) designation is C200x27.9: 203 mm deep with a 64.3 mm flange and 27.9 kg/m.
Where is the centroid of a C8x18.75 channel?
A channel is not symmetric about its vertical axis. The centroid of C8x18.75 sits 0.565 in (14.4 mm) from the back of the web, and the shear center is 0.431 in from the web centerline, on the side away from the flanges.
What size load can a C8x18.75 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.