WireGaugeCalc Free calculator · NEC cited · works offline
Emt Conduit Fill
emt conduit fill is quick to verify with WireGaugeCalc, since the app uses the NEC Chapter 9 area tables.
You enter conduit size, conductor type, and count, so the calculator compares the wire area to the allowed fill.
That keeps you under the 40 percent limit before you start pulling.
Open the calculatorFill against NEC Chapter 9, Table 1 (40% for 3+ conductors) with Table 4 and Table 5 areas. Field aid only, verify against the current NEC and your local authority having jurisdiction.
How EMT Fill Is Measured
Chapter 9 caps three or more conductors at 40 percent of the conduit area, so the wire cannot fill more than that fraction.
Each conductor has a listed cross section by insulation type, so THHN and XHHW take different room.
The calculator adds those areas and shows the percent used against the limit.
Sizing Conduit With The 40 Percent Rule
Conduit fill for 2 inch EMT and other sizes depends on a few inputs:
- Conduit trade size, such as 1/2 inch through 2 inch EMT
- Conductor gauge and insulation type
- The number of conductors in the run
- The 40 percent limit for three or more conductors
- Chapter 9 area tables for EMT, PVC, and RMC
One app for every NEC calculation
WireGaugeCalc keeps the calculations you reach for most in one place:
- Voltage drop and wire sizing for any run
- Conduit fill for EMT, PVC, and RMC
- Box fill and junction box sizing
- Ampacity and temperature derating
- Motor circuit and load calculations
- Conduit bend offsets and saddles
Built for the field, works offline
The whole app runs on your phone, so it keeps working in a basement, an attic, or a job site with no signal.
There is no account to create and nothing to load. Open it, run the number, and get back to work.
- No signup and no signal needed
- Answers in a tap, not a spreadsheet
- Same tool on phone, tablet, and desktop
Every result cites the NEC article
Each answer shows the table or formula it came from, so you can check the method and learn the code as you go.
That makes the app useful on the job and during exam prep, since the reasoning is right next to the number.
Switch the code year your job runs on
Jurisdictions adopt the NEC at different times, so you can match the calculation to the code in force:
- NEC 2017, 2020, and 2023 tables
- Copper and aluminum conductors
- 60, 75, and 90 degree C terminations
- Single-phase and three-phase systems
Run the number, then get back to work
Stop flipping through a paper book or hopping between calculator sites. Enter your values, read the code-cited answer, and move on. Free to use, no signup.
Open the calculatorFrequently asked questions
What is the fill limit for EMT?
For three or more conductors, NEC Chapter 9 allows 40 percent of the conduit interior area. The calculator shows the percent used so you stay under it.
How many THHN conductors fit in 2 inch EMT?
It depends on the gauge, since each conductor has a listed area, so the count varies by wire size. Enter the gauge and the app returns the maximum for 2 inch EMT, then confirm with the current NEC and your local authority having jurisdiction.
Does EMT fill differ from PVC fill?
Yes, the interior area differs by raceway type, so EMT, PVC, and RMC each have their own Chapter 9 dimensions. The calculator uses the table that matches your conduit.
Is WireGaugeCalc free to use?
Yes. Every calculator is free to run with no signup. A paid tier adds saved projects, PDF reports, and extra code years, but the core math stays free.
Does it work without internet?
Yes. The app runs on your device, so it keeps working with no signal on a job site, in a basement, or in an attic.
Are the results code accurate?
Results follow published NEC tables and standard formulas, and each answer shows the article it came from. It is a field aid, not a stamp of approval, so verify against the current code and your local authority before you wire anything.
Which NEC code year does it use?
You can switch between NEC 2017, 2020, and 2023, since jurisdictions adopt the code at different times. Pick the year your job runs on.