Conduit Fill Calc

Fast, accurate conduit fill calculator for NEC & CEC — built for electricians.
Stop flipping through code books and squinting at fill tables. Conduit Fill Calculator gives you instant, accurate conduit fill percentages for the National Electrical Code (NEC) and Canadian Electrical Code (CEC) — right from your phone.

DUAL CODE SUPPORT

Switch between NEC and CEC with a single tap.

The app automatically adjusts conduit sizes, wire types, and data to match each standard:

NEC: Imperial sizes with THHN, XHHW, RHW
CEC: Metric sizes (16mm–103mm) with T90, RW90, RPV90

All calculations are based on verified code tables.

EVERY CONDUIT AND WIRE COMBINATION

EMT, PVC Schedule 40/80, IMC, and RMC across trade sizes from 1/2" to 4".
Wire sizes from 14 AWG to 500 kcmil.

Thousands of combinations calculated instantly — no tables, no guesswork.

THREE SIMPLE INPUT MODES

Wire mode: Enter wire type, gauge, and count
Circuit mode: Enter circuits by type — the app calculates conductors automatically
Mixed wire mode: Combine multiple wire types and sizes in one conduit

SIZE MY CONDUIT

Instantly find the minimum compliant conduit size across all conduit types.
Visual fill bars show exactly where you stand so you can make the right call fast.

FILL TARGETS

Work the way you prefer:
Code Max (40%)
Conservative (35%)
Easy Pull (30%)
Automatically applies correct limits:
53% for one conductor
31% for two
40% for three or more

SMART WARNINGS

Jam ratio alerts (2.8–3.2 danger zone)
Ampacity derating warnings when conductor count exceeds code thresholds
Clear pass/fail status with color indicators
Pull difficulty ratings (Easy, Moderate, Difficult)

MAX CAPACITY MODE (FIND MAX FILL)

Set conductor count to zero and instantly see the maximum number of wires or circuits that fit in your selected conduit — perfect for planning runs.

SAVE, COPY, AND COMPARE

Save calculations for quick access on the job
Copy formatted results into estimates or emails
Rename and organize saved runs

BUILT FOR THE FIELD

Works 100% offline
No account required
No data collected
One-handed, portrait-optimized design
Instant updates as inputs change
Automatically restores your last setup

IDEAL FOR REAL-WORLD JOBS

Conduit fill for residential, commercial, and industrial installations
EMT, PVC, IMC, and RMC conduit runs
Panel feeders, branch circuits, and service entrances
Motor circuits, multi-wire branch circuits, and three-phase systems
Planning conduit runs before pulling wire
Verifying code compliance on-site

DESIGNED FOR ELECTRICIANS AND CONTRACTORS

Whether you're an apprentice, journeyman, or master electrician, this tool helps you work faster and more accurately. Perfect for use on job sites, during inspections, or when preparing estimates and material lists.

KEYWORDS & COVERAGE

Conduit fill calculator, conduit sizing, electrical calculator, NEC calculator, CEC calculator, wire fill, conduit capacity, ampacity reference, AWG wire sizing, kcmil conductors, EMT fill chart, PVC conduit fill, IMC and RMC sizing, electrical code reference, electrician tools.

REFERENCE, NOT ADVICE

Calculations are based on NEC (NFPA 70) Chapter 9 Tables 1, 4, and 5, and CEC (CSA C22.1) Section 12 Tables 6, 8, and 9A.
Always verify with your local Authority Having Jurisdiction (AHJ).
Whether you're roughing in residential, planning commercial runs, or checking service entrance fill — get the right answer in seconds.