Conduit Offset Bend Calculator

Two numbers do it. The distance between the two bend marks equals the offset depth times the multiplier for your bend angle: multiplier is 1/sin(angle), so 30 degrees = 2, 45 degrees = 1.4, and 22.5 degrees = 2.6. Then account for shrink, the amount the conduit shortens along its run, which is a fixed amount per inch of offset depth for each angle (30 degrees = 1/4 inch per inch). For example, a 6-inch offset at 30 degrees puts the marks 12 inches apart (6 x 2) and shrinks the run 1.5 inches (6 x 1/4).

The multiplier is 1 divided by the sine of the bend angle, and it converts the offset depth into the distance between your two bend marks. The common ones electricians memorize are: 10 degrees = 6, 22.5 degrees = 2.6, 30 degrees = 2, 45 degrees = 1.4, and 60 degrees = 1.2. A larger angle gives a smaller multiplier, so the bends sit closer together but the run shrinks more.

30 degrees is the most common all-around choice because its multiplier is exactly 2, making the math easy, and its shrink is moderate. Use a smaller angle like 10 or 22.5 degrees for a long, gentle offset that pulls wire easily; use 45 degrees for a tight offset around a close obstacle, accepting more shrink and a harder pull. Match the angle to the space and keep both bends the same angle.

Shrink is how much shorter the conduit becomes along its straight run once you put the offset in it, because the diagonal travel between the bends uses up length. You subtract it so the fittings still land where you need them. It is a fixed amount per inch of offset depth by angle: 1/16 inch at 10 degrees, 3/16 at 22.5, 1/4 at 30, 3/8 at 45, and 1/2 at 60 degrees. Deeper offsets and steeper angles shrink more.