Wire Ampacity Calculator
Look up NEC 310.16 style ampacity by AWG, material, and temperature column. Default 12 AWG copper at 75 °C uses the table ampacity with optional derating. Informational, not code approval.
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How to look up wire ampacity
- Enter AWG gauge. Default is 12.
- Pick copper or aluminum and 60, 75, or 90 °C column.
- Optionally enter a derating factor between 0 and 1.
- Confirm with local code and installation conditions. Nothing is uploaded.
Wire ampacity
NEC 310.16 style table
| AWG | American Wire Gauge size |
|---|---|
| Copper vs aluminum | Separate table columns |
| Temperature | 60, 75, or 90 °C column |
| Derating | Optional multiplier on table value |
| Default | 12 AWG copper, 75 °C |
| Approval | Informational. Not NEC approval. |
Table lookup
The engine reads bundled NEC-style ampacity rows for copper or aluminum at the selected temperature column. Default 12 AWG copper at 75 °C returns the table ampacity before optional derating.
Derating factor
Ambient temperature, conduit fill, and bundling may require derating below the table. Type a factor ≤ 1 to scale the table value; confirm rules locally.
AWG geometry
Cross-section in mm² from gauge is AWG to mm², separate from ampacity.
Voltage drop
Length and load current for drop are on voltage drop.
Limits
Table snapshot only.
The formula runs in this tab. CZNull does not receive the numbers.
Informational only. Not wiring, code, or manufacturer approval. See the disclaimer.