AWG Wire Size Chart - Guide
Cross-reference AWG and kcmil conductor sizes with NEC 310.16 ampacity (copper & aluminum, 60/75/90 °C), cross-sectional area, diameter, and DC resistance. Filter, sort, select rows, and export to CSV. Free, no sign-up.
Guide
This AWG wire size chart lets you cross-reference standard conductor sizes — from 14 AWG up through 2000 kcmil — against the values electricians look up most: allowable ampacity for copper and aluminum at the 60 °C, 75 °C, and 90 °C insulation ratings, plus cross-sectional area, conductor diameter, and DC resistance. Filter by size class, sort any column, select rows, copy single values, and export to CSV — all in the browser, with no sign-up. Ampacity follows NEC Table 310.16; area, diameter, and resistance follow NEC Chapter 9, Table 8.
AWG and kcmil sizing
American Wire Gauge (AWG) numbers run backwards: the larger the gauge number, the smaller the conductor. A 14 AWG wire is thinner than 6 AWG, and every drop of three gauge numbers roughly doubles the cross-sectional area. Once conductors get larger than 4/0 AWG (“four-aught”), sizing switches to thousands of circular mils, written kcmil (for example 250 kcmil or 500 kcmil). One circular mil is the area of a circle 0.001 in in diameter, so the area column is a direct measure of how much metal carries the current.
Use the AWG and kcmil chips at the top of the table to show one size class at a time, or type a size such as 12, 4/0, or 250 in the search box.
Reading the ampacity columns
Ampacity is the continuous current a conductor can carry without exceeding its insulation temperature rating. NEC Table 310.16 lists three ratings for each conductor, and the chart shows all three for both copper and aluminum.
| Column | What it means |
|---|---|
| 60 °C | Types such as TW/UF. Also the column the NEC forces you to use for 14–1 AWG terminations in many cases. |
| 75 °C | Types such as THW/THWN/XHHW. The workhorse column, because most lugs and breakers are rated 75 °C. |
| 90 °C | Types such as THHN/THWN-2/XHHW-2. Used mainly as the starting point for derating, not for final termination sizing. |
Terminal temperature rule (NEC 110.14(C)). You may only use a column up to the temperature rating of the weakest part of the circuit — the conductor, the lug, and the device terminal. In practice that usually means sizing from the 75 °C column even when 90 °C insulation is installed. The 90 °C value is still useful as the base figure before applying correction factors.
Why these are baseline values (derating)
The ampacities in Table 310.16 assume an ambient of 30 °C (86 °F) and no more than three current-carrying conductors in the raceway or cable. Real installations are often hotter or more crowded, so the table value is a starting point, not the final answer. Two corrections apply:
| Correction | Reference |
|---|---|
| Ambient temperature | Multiply by the factor from NEC 310.15(B)(1) when the ambient differs from 30 °C. |
| Conductor count | Apply the adjustment from NEC 310.15(C)(1) when more than three current-carrying conductors share a raceway. |
Start from the 90 °C column, apply both factors, and then confirm the result does not exceed the 75 °C termination limit. The chart gives you the table values; the correction math is a separate step.
Area, diameter, and DC resistance
Turn on the optional columns from the Columns menu to see the conductor properties from NEC Chapter 9, Table 8.
| Column | Use |
|---|---|
| Area (circular mils / mm²) | Cross-sectional metal area — drives both ampacity and resistance, and feeds equipment grounding and conduit-fill checks. |
| Diameter (in) | Overall stranded conductor diameter, the starting point for raceway and cable-tray fill estimates. |
| DC resistance (Ω/kFT) | Resistance per 1,000 ft at 75 °C for copper and aluminum — the base value for voltage-drop calculations. |
Filtering, sorting, and sharing
Type a size in the search box, or tap the AWG/kcmil chips, to narrow the list. Click any column header to sort ascending or descending — handy for finding the smallest conductor that meets a target ampacity. Tap any number to copy it, or use the copy icon on a header to grab the whole column. Check one or more rows to copy them or download a CSV that pastes straight into a spreadsheet take-off. Press Share link to copy a URL that reproduces your current filter, sort, and selection for a colleague.
Sources and disclaimer
Ampacity values are from NEC Table 310.16 (allowable ampacities at 30 °C ambient, not more than three current-carrying conductors). Area, overall diameter, and DC resistance are from NEC Chapter 9, Table 8 (uncoated copper and aluminum, stranded, DC resistance at 75 °C); mm² is converted from circular mils. Aluminum is not listed for 14 AWG.
This chart is a quick reference for planning and estimating. Final conductor sizing must account for terminal temperature limits, ambient and conductor-count corrections, voltage drop, and your local code edition and amendments. Always verify against the current NEC and the authority having jurisdiction.