Conduit Cut Length Calculator
Every 90-degree bend in a conduit run creates gain — a small amount of length that the conduit "saves" because the curved path through the bend is shorter than the two straight tangent lines that meet at the bend point. If you cut your conduit to the full finished measurement without subtracting this gain, the piece will end up too long after bending.
This calculator takes your desired finished length, the number of 90-degree bends, and your conduit type and size. It returns the gain per bend, total gain, and the exact cut length so your conduit fits the first time.
Cut Length Formula
Cut Length = Finished Length − (Number of Bends × Gain)
Gain = (2 × Radius) − Deduct for a 90° bend
Gain is determined by the bending radius and the deduct value for your specific conduit type and size. For example, 1/2-inch EMT has a radius of 4 inches and a deduct of 5 inches, giving a gain of 3.125 inches per 90-degree bend.
Gain Values by Conduit Type
| Conduit | Size | Radius | Deduct | Gain |
|---|---|---|---|---|
| EMT | 1/2" | 4" | 5" | 3.125" |
| EMT | 3/4" | 4.5" | 6" | 3.375" |
| EMT | 1" | 5.75" | 8" | 3.5" |
| EMT | 1-1/4" | 7.25" | 11" | 2.625" |
| EMT | 1-1/2" | 8.25" | 13" | 1.875" |
How to Use This Calculator
- Enter the finished length — the end-to-end measurement you need after all bends are made. You can enter inches, feet-inches, or fractions.
- Enter the number of 90-degree bends — count every 90-degree bend in the run.
- Select conduit type and size — this determines the gain per bend.
- Read the results — Cut Length is the measurement to mark and cut your conduit before bending.
Use the unit switcher above the results to toggle between feet-inch-fraction, decimal feet, decimal inches, and metric output.
Worked Example
- Finished length: 48 inches (4 feet)
- Number of bends: 2 (two 90-degree bends)
- Conduit: 1/2" EMT (gain = 3.125" per bend)
- Total gain: 2 × 3.125 = 6.25 inches
- Cut length: 48 − 6.25 = 41.75 inches (3' 5-3/4")
Frequently Asked Questions
Why do I need to account for gain when cutting conduit?
When conduit is bent, the path through the curve is shorter than the two straight tangent lines that meet at the bend point. This difference is called gain. If you cut the conduit to the full finished length without subtracting gain, the conduit will end up too long after bending. Each 90-degree bend adds a few inches of gain, and the amount depends on your conduit type and size.
How do you calculate conduit cut length?
Cut length equals the finished end-to-end length minus the total gain from all bends. Total gain is the gain per bend multiplied by the number of bends. For example, with 1/2-inch EMT that has a gain of 3.125 inches per bend, a 48-inch finished piece with two bends would need a cut length of 48 - (2 x 3.125) = 41.75 inches.
Does gain change with conduit type and size?
Yes. Gain depends on the bending radius and deduct of the conduit, both of which change with conduit type (EMT, IMC, Rigid) and size (1/2 inch through 1-1/2 inch for hand benders). Larger conduit has a larger bending radius and different deduct values, which changes the gain per bend. Always use the correct gain for your specific conduit.