Conduit Bending Calculator
Calculate offset bends, stub-ups, and back-to-back bends for EMT conduit with deduction and shrinkage values.
Results
Visualization
How It Works
Conduit bending requires precise calculations to achieve accurate bends. The three most common bends are 90-degree stub-ups, offset bends to navigate around obstacles, and back-to-back bends for U-shaped routes.
The Formula
Stub-up: Mark = Stub Height - Deduction
Offset: Distance Between Bends = Depth / sin(Angle)
Shrinkage = Depth × Shrinkage Multiplier
Offset: Distance Between Bends = Depth / sin(Angle)
Shrinkage = Depth × Shrinkage Multiplier
Variables
- Deduction — Take-up for 90-degree bends (varies by conduit size: 1/2"=5", 3/4"=6", 1"=8", 1-1/4"=11")
- Depth — The perpendicular distance the conduit must offset
- Angle — The bend angle used for the offset (commonly 30 or 45 degrees)
- Shrinkage — The amount the overall run shortens due to the offset bends
Example
A 6-inch offset at 30 degrees in 1/2" EMT: Distance between bends = 6 / sin(30) = 12 inches. Shrinkage = 6 x 1/4 = 1.5 inches. Mark your first bend, then measure 12 inches for the second.
Tips
- Always measure and mark twice before bending.
- For stub-ups, the deduction accounts for the radius of the bend shoe.
- The 30-degree offset is the most commonly used angle in commercial work.
- Anti-dog (reverse bend correction) is needed when conduit sags between bends.
- Practice on scrap conduit before bending expensive pieces.