Conduit Gain Chart

Gain is the amount of conduit a 90-degree bend saves compared to two straight pieces meeting at a square corner. Because the bend follows a curved radius instead of a sharp right angle, the finished path is shorter than the two leg measurements added together. In the field you measure legs to the outside corner, so the gain you subtract is 2.42 inches for 1/2-inch EMT. You subtract the gain from the summed leg lengths to find how much conduit to actually cut.

It is called gain. The arc of a 90-degree bend is shorter than the two straight legs measured to the corner, and that difference is the gain. Measured to the outside corner the way a tape reaches it, the standard EMT hand-bender gain is 2.42 inches for 1/2 inch, 2.85 inches for 3/4 inch, 3.63 inches for 1 inch, and 4.62 inches for 1-1/4 inch. Subtracting gain is what makes a multi-bend piece come out to the correct overall length.

Because a 90 has two corners you could measure to. The pure arc savings is centerline only: the curved centerline is 1.72 inches shorter than routing to the centerline corner on 1/2-inch EMT. But a tape measures to the outside corner, which sits one full conduit outside diameter (0.706 inch on 1/2-inch EMT) farther out. So the gain you actually subtract from a tape layout is one diameter larger than the arc savings: 2.42 inches, versus 1.72 inches at the centerline. Field charts and manufacturer tables list the 2.42-inch outside value; the 1.72-inch centerline value is the geometry underneath it.

Developed length is the total conduit needed for a piece with bends. Add the leg dimensions measured to the outside corner, then subtract the gain for each 90-degree bend: developed length = sum of legs minus (gain x number of 90s). For an L-shape with a 12-inch and an 18-inch leg in 1/2-inch EMT, developed length = 12 + 18 - 2.42 = 27.58 inches. Cutting to the summed 30 inches would leave the piece too long.

No. Take-up (also called deduct) is used to place the bend mark for a single 90: it is the distance from the bender arrow to the back of the finished bend, subtracted from the stub height. Gain is used when figuring the total length of conduit for a run with bends. Take-up positions the mark; gain sizes the overall piece. Both come from the bend radius but they solve different problems.

Yes. Larger conduit has a larger bend radius and a larger diameter, so its 90-degree bends save more material and the gain is larger: 2.42 inches for 1/2 inch up to 4.62 inches for 1-1/4 inch EMT. This is the opposite of offset shrink, which depends only on the bend angle and is the same on every conduit size. Always use the gain that matches the conduit you are bending.