Corner Bend Calculator
When conduit needs to turn a corner, the bend angle you put into the conduit is not the same number as the corner angle. The relationship is straightforward: the bend angle equals 180 degrees minus the corner angle. This calculator does the math for you and also returns the deduct and gain based on your conduit type and size.
How Corner Angles Relate to Bend Angles
For a standard 90-degree corner — the kind where two walls meet at a right angle — you need a 90-degree bend in the conduit. That one is easy to remember because the numbers happen to match.
For a 45-degree corner, you need a 135-degree bend. That is because the conduit has to change direction by 180 − 45 = 135 degrees to follow the corner. The sharper the corner, the larger the bend angle required.
For an obtuse 120-degree corner, you only need a 60-degree bend. Wider corners require gentler bends. This comes up when conduit follows walls that meet at odd angles, or when routing around angled architectural features.
Bend Angle = 180° − Corner Angle
Works for any corner from 1° to 180°
Understanding Deduct and Gain
The deduct is the tangent length of the bend arc. When you position conduit in the bender, you subtract the deduct from your measurement to place the bend at the correct location. The deduct value depends on the bending radius, which varies by conduit type and size.
Gain is the difference between the two tangent lengths and the arc length. Because the path through the bend is shorter than the two straight segments would suggest, you cut the conduit shorter than the finished measurement. Gain tells you exactly how much shorter.
How to Use This Calculator
- Enter the corner angle — the angle formed by the two surfaces the conduit must follow. A standard wall corner is 90 degrees.
- Select conduit type — EMT, IMC, or Rigid. Each type has a different bending radius.
- Select conduit size — from 1/2" to 1-1/2". Larger conduit has a larger bending radius.
- Read the results — Bend Angle is the degree of bend to put in the conduit. Deduct and Gain help you position and cut the conduit correctly.
Frequently Asked Questions
How do you calculate the bend angle for a corner?
The bend angle needed to turn a corner is 180 degrees minus the corner angle. For a standard 90-degree corner you need a 90-degree bend. For a 45-degree corner you need a 135-degree bend. For a 120-degree corner you only need a 60-degree bend.
What is the deduct for a corner bend?
The deduct for a corner bend is the tangent length of the bend arc. It depends on the bender radius and the bend angle. You subtract the deduct from your measurement to position the conduit correctly in the bender. The deduct changes with conduit type and size because each has a different bending radius.
What is gain in a conduit bend?
Gain is the difference between the sum of the two tangent lengths and the arc length of the bend. When you bend conduit, the path through the bend is shorter than the two straight legs would suggest. Gain tells you how much shorter the conduit needs to be cut to achieve the correct finished length.