Need to know exactly what size conduit to run – and how many conductors will fit – without dragging out the NEC® tables?
This free conduit sizing tool lets you size electrical conduit in seconds using NEC® conduit fill rules.
Choose your conductors, select a raceway, and the online conduit fill calculator shows:

• Required conduit trade size
• Conduit fill percentage
• Whether the run passes standard NEC fill limits

Use it as your everyday electrical conduit size calculator and electrical pipe fill calculator for residential, commercial, and solar projects.

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Instant Electrical Conduit Size Calculator (NEC-Based)

Instead of flipping through Chapter 9 tables, this electrical conduit size calculator does the math for you.

1. Select conduit type (EMT, PVC, rigid, flex, etc.).
2. Enter conductor sizes, insulation, and quantity.
3. See conduit area, wire area, and fill percentage.
4. Adjust conductor mix until the electrical pipe size calculator shows a compliant result.

You get a simple answer to the question:
“What size conduit do I need for these wires?”

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Electrical Pipe Fill Calculator – How It Works

The electrical pipe fill calculator follows the standard NEC fill limits:

• 1 conductor – up to 53% fill
• 2 conductors – up to 31% fill
• 3 or more conductors – up to 40% fill

The tool compares total conductor area to the internal area of the conduit size you select, then displays the conduit fill percentage and whether it’s within the allowed limit.

It’s the same logic you’d use by hand, just a lot faster.

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Why Use an Online Conduit Fill Calculator Instead of Charts?

Printed charts and PDFs are fine until:

• You mix different wire sizes or insulation types
• You’re switching between EMT, PVC, and rigid
• You’re trying to keep track of multiple options for value-engineering

An online conduit fill calculator:

• Updates instantly when you change wire size or quantity
• Works on laptop, tablet, or phone
• Keeps the calculations consistent across your entire team

If you’re doing more than one conduit run, a browser-based conduit sizing tool is simply quicker and hardr to mess up.

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EMT Hole Saw Size Chart

Sizing the conduit is one thing; drilling the opening is another.
Use this EMT hole saw size chart as a quick guide when you’re drilling panels or enclosures.

Hole saw size chart for EMT*

• 1/2″ EMT – ~7/8″ hole saw
• 3/4″ EMT – ~1 1/8″ hole saw
• 1″ EMT – ~1 3/8″ hole saw
• 1 1/4″ EMT – ~1 3/4″ hole saw
• 1 1/2″ EMT – ~2″ hole saw
• 2″ EMT – ~2 1/2″ hole saw

*Always confirm with connector and enclosure manufacturer requirements.

This section targets searches like “emt hole saw size chart”, “hole saw size chart for emt”, and “hole saw size for 3 emt connector” without sending anyone off this page.

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Southwire Conduit Fill Calculator Searches

If you landed here searching for:

• southwire conduit fill calculator
• conduit fill calculator southwire
• southwire fill calculator
• southwire wire fill calculator

you’re in the right place.

This conduit sizing page follows the same basic NEC conduit fill logic you’d expect from any professional calculator, but it runs directly in the browser with no app download or login. Just pick your conduit, enter your wires, and read the result.

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FAQ: Conduit Sizing Tool & Conduit Fill

What is a conduit sizing tool?
A conduit sizing tool is a simple calculator that takes conductor size, insulation type, and quantity, and tells you what conduit size will keep fill within NEC limits.

Is this an electrical pipe fill calculator or an electrical pipe size calculator?
Both. It works as an electrical pipe fill calculator when you already know the conduit size and want to check fill, and as an electrical pipe size calculator when you want to know which size conduit to use.

How accurate is the conduit fill percentage?
The conduit fill percentage is based on standard conductor and raceway dimensions and the NEC fill rules. It’s meant for real-world design and checking, not as a replacement for local code or inspector judgment.

Can I use this instead of manufacturer apps?
Yes. If you normally hunt for a Southwire conduit fill calculator or similar manufacturer app, this browser-based calculator gives you the same kind of answer without leaving the page.

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Use this page as your go-to conduit sizing tool, electrical conduit size calculator, and online conduit fill calculator whenever you need a quick, code-compatible answer to “What size conduit should I run for these wires?”