Table 4 and Table 5 of the 2026 edition are in this page. Pick a raceway, add the conductors, read the fill percent and the size that fits.
The conduit bending simulator handles the other half of the run. Drag the rise, turn the angle dial, and it works the offset multiplier, the shrink, the take up and every mark, then counts the degrees you have put in against the 360 that 358.24(B) allows between pull points.
One row per insulation type and size. Grounds count toward fill under Note 3, so give them a row.
Note 4 to Table 1: 60 percent, and no count adjustment factors.
This is the Annex C question. It holds only where every conductor in the raceway is the same size and the same insulation type, which is also the condition on the rounding rule underneath it.
The calculators on the /calc page make you read every table value out of your own book, because looking a value up is the skill the exam is testing. This page does the opposite on purpose, so a pull can be checked from the truck in about ten seconds.
Both run the same rules. The method is written out below, and every number the calculator uses is printed further down as a table you can read straight off.
Conduit fill is one comparison. Total the cross sectional area of every conductor from Chapter 9, Table 5, then hold that total against a percentage of the raceway area from Chapter 9, Table 4. The percentage itself comes from Chapter 9, Table 1.
What sets the percentage is the number of conductors, not their size. Table 1 gives 53 percent for one conductor, 31 percent for two, and 40 percent for three or more. Two is the tightest of the three, which reads backwards until you remember the limit is about pulling tension rather than heat.
Note 4 to Table 1 is the exception worth carrying in your head. A nipple not over 24 inches long, run between boxes, cabinets or similar enclosures, may be filled to 60 percent, and the same note turns off the conductor count adjustment factors over that length. Both conditions have to be true, and a length of 25 inches is an ordinary raceway again.
Note 3 puts equipment grounding and bonding conductors into the fill at their own area, bare or insulated. Exam items lean on this, because a candidate who leaves the ground out of a four conductor pull lands on an answer that looks reasonable.
Run backwards, from a raceway to a count, the arithmetic divides the permitted area by the area of one conductor and lands on a decimal. Note 7 decides what happens to it: where every conductor is the same size, a decimal of 0.8 or larger goes up to the next whole number, and anything under that is dropped. Get the condition wrong and you have swapped one wrong answer for another, because on a mixed size pull the decimal is always dropped.
The order that saves time is this. Count the conductors first, because that fixes the percentage, then check for the nipple, then read Table 5 by insulation type before size, total the areas, and only then open Table 4 at the right article. The study page on conduit fill works through the notes one at a time.
Four 12 AWG THHN into half inch EMT. Table 5 gives 0.0133 square inches for one 12 AWG THHN, so four of them come to 0.0532 square inches.
Four conductors is more than two, so Table 1 gives 40 percent. Table 4 gives 0.304 square inches of total area for half inch EMT, and 40 percent of that is 0.122 square inches.
0.0532 against 0.122 passes, at 17.5 percent fill. Turn the same two numbers around and 0.122 divided by 0.0133 gives 9 conductors as the maximum, which is what Annex C prints for 12 AWG THHN in half inch EMT.
The value used for your inputs is read from NEC 2026 Chapter 9 Table 1, Table 4 and Table 5, the way you would read it in the exam room, and the working above names the row it came from. The tables themselves belong to NFPA and are not printed on this page. Bring your own copy of the 2026 code, which is what the exam requires anyway, and check the row there.
These are the values the calculator runs on. Only the total area of each raceway is stored here. The 53, 31, 40 and 60 percent figures are computed from that total rather than typed in from the printed percentage columns of Table 4, and they agree with those columns to the thousandth.
| Conductors in the raceway | Permitted fill |
|---|---|
| 1 | 53% |
| 2 | 31% |
| Over 2 | 40% |
| Nipple not over 24 inches | 60% |
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