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Conduit Size Calculator
Choose a conduit size from the cable count and diameter using the 40 percent fill rule.
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Compare Your Options And Get Clear Answers
Choose a conduit size from the cable count and diameter using the 40 percent fill rule.
Conduit Size Estimator
Enter your numbers below for an instant estimate.
0
💡 Tip: Conduit area >= total cable area / fill fraction.
How It Works
Key concepts behind this calculator
1
Enter Values
Fill in each field with your own numbers.
2
Calculate
Results update as you change the inputs.
3
Review
Read the breakdown and the explanation.
4
Adjust
Change values to compare scenarios.
Quick Reference Guide
Conduit Quick Guide
Typical values for reference.
| Cables | Diameter mm | Fill % | Conduit |
|---|---|---|---|
| 6 | 8 | 40 | 40 mm |
| 3 | 6 | 40 | 20 mm |
| 10 | 10 | 40 | 63 mm |
| 2 | 12 | 53 | 32 mm |
| Rule of Thumb | Check inputs | Use as a guide | Round sensibly |
Common Questions
Conduit Size Calculator FAQ
Answers to common questions about this calculator.
Cables should fill no more than 40 percent of the conduit area for three or more wires.
It eases pulling and allows heat to escape.
No, more bends require extra room.
No, always follow local regulations.