AWG to mm² Conversion & Current Rating Chart

Converting between American Wire Gauge (AWG) and metric conductor sizes is straightforward as a dimensional comparison—but choosing a safe cable is not. This guide gives engineers and buyers an AWG to mm² conversion chart, explains what an AWG current rating does and does not mean, and shows how to check a proposed size against the actual installation.

Quick answer: AWG numbers run in reverse: a smaller gauge number means a larger nominal conductor. AWG and metric mm² sizes are not exact equivalents. For example, 0.50 mm² is close to 20 AWG (0.518 mm²), but 1.50 mm² is larger than 16 AWG (1.31 mm²). AWG alone cannot establish ampacity; conductor material, insulation system, terminals, installation and applicable electrical rules also matter.

What Is AWG (American Wire Gauge)?

AWG describes nominal conductor size. In the standard round-wire progression, 4/0 AWG is larger than 1/0 AWG, which is larger than 1 AWG; 24 AWG is much smaller. For a solid, round conductor, nominal diameter and geometric area can be related mathematically. ASTM B258-18(2026) covers standard nominal diameters and cross-sectional areas of AWG solid round wires. For stranded or compacted conductors, verify the construction and electrical resistance in the applicable product specification rather than treating a solid-wire diameter as the finished cable diameter.

• Gauge direction: a lower AWG number means a larger nominal conductor.
• Approximate progression: moving down three gauge numbers roughly doubles conductor area; moving down six roughly doubles diameter.
• Nominal size is not capacity: AWG does not by itself state the permitted current, voltage rating or suitability of a complete cable.

AWG Wire Size and mm² Conversion Chart

The chart below lists nominal solid-round conductor geometry, calculated from the AWG diameter progression. Values are rounded for reference; they are not cable outer diameters or permissible currents. Check the relevant conductor or cable standard for the exact specification being purchased.

mm² to AWG Conversion: Comparison vs Substitute

Metric sizes and AWG sizes form different series. The common comparison column reflects widely used cross-reference numbers, including familiar even gauges; it does not mean equal area or electrical interchangeability. “Difference” is (AWG nominal area ÷ metric target area − 1) × 100. A negative value means the comparison AWG has less geometric area. The final column shows the first nominal AWG size whose solid-round geometric area is at least the stated metric area; odd AWG sizes may not be available in the required cable construction.

Closest AWG Size vs Equal-or-Larger AWG Size

Consider a requirement of at least 1.50 mm². The common comparison 16 AWG has about 1.31 mm², so it does not meet that geometric minimum. The first nominal AWG above it is 15 AWG at about 1.65 mm². If 15 AWG is unavailable in the required cable type, the next available larger conductor—for example 14 AWG—may be considered. Neither step is automatic approval: compare conductor resistance, ampacity under the actual installation, terminal compatibility, cable standard, certification and the project specification. A specified metric size may require that exact designation, regardless of nominal area.

For a wider selection workflow, use our cable size and cross-section selection guide. The relationship between area and resistance is explained in our cable resistance formula guide.

AWG Current Rating: Why There Is No Universal Ampacity

An AWG number alone does not define a universal current rating. Ampacity is the current a conductor can carry under stated conditions without exceeding its allowed temperature. The result depends on conductor material, insulation and complete cable construction, terminal temperature limits, ambient temperature, the number of loaded conductors, grouping, installation method and applicable code. A free-air value cannot be presented as though it were a value from NEC Table 310.16.

The following examples show why conditions must travel with the number. They use copper conductors in the 75°C column of NEC Table 310.16, 30°C ambient, no more than three current-carrying conductors in raceway, cable or directly buried installation. They are base-table values, not a final design or an approval for a specific product. Equipment termination limits, correction/adjustment factors and conductor-use rules must still be checked; 14 and 12 AWG also have specific small-conductor overcurrent-protection restrictions. These conditions are not “single conductor in free air.”

Do not use this reference table as a product rating or circuit design answer. The adopted code edition and jurisdiction govern. Consult the applicable NEC table and its notes, the cable datasheet and the equipment instructions. NFPA’s NEC development material documents the Table 310.16 installation basis; NFPA’s ampacity workflow resource highlights the need for corrections and adjustments. For the complete method, see our cable ampacity calculation guide.

24 AWG Current Rating: Why Installation Changes the Answer

24 AWG has a nominal solid-round area of about 0.205 mm² and diameter of about 0.511 mm. There is no universal “24 AWG = 2 A” rule. A small conductor may be used for signal, control or equipment wiring, but permissible current depends on its insulation system, conductor construction, bundle temperature, installation, termination and the product’s applicable listing or standard. Do not extend the NEC Table 310.16 examples above to 24 AWG; that table does not supply a general 24 AWG row.

For a real construction example, see the UL 10485 PFA high-temperature wire product data, which includes a 24 AWG option and conductor details. Its electrical suitability must still be checked against the project’s operating conditions; its AWG designation alone is not an ampacity claim.

How to Select AWG for an Industrial Cable

1. Define the load and duty: identify operating current, starting conditions and whether any continuous-load factor is required by the applicable NEC article or equipment rule. Do not apply 125% universally.
2. Identify the installed cable: confirm conductor material, strand construction, insulation, jacket, voltage rating, environment and relevant product standard. Material names such as rubber, PVC or silicone alone do not establish allowable conductor temperature or ampacity.
3. Apply installation rules: use the appropriate ampacity method for raceway, cable, burial or free air; check ambient-temperature correction, grouping and terminal temperature limitations.
4. Check the run length: calculate voltage drop and resistance under the actual circuit conditions. NEC informational guidance commonly references approximately 3% for a feeder or branch-circuit segment and 5% total feeder-plus-branch drop; project requirements may differ. See our cable voltage drop calculation guide.
5. Confirm physical fit and documents: check terminals, bending and flexing duty, product datasheet, required approvals and purchasing specification before substituting an AWG for a metric conductor.

If you already know the load current and need a complete conductor-size workflow, use amps to cable size. For North American portable-cord construction, compare the actual SOOW and SJOOW portable cord options rather than choosing from gauge alone.

Common AWG Selection Mistakes

• Treating the “common comparison” AWG in a conversion chart as an equal-or-larger metric substitute.
• Using one ampacity number without its conductor material, temperature column and installation basis.
• Applying a free-air figure to a raceway or multi-conductor cable, or forgetting adjustments when the number of current-carrying conductors exceeds the relevant table basis.
• Assuming a higher insulation temperature automatically permits a higher circuit current when terminals or equipment impose a lower limit.
• Ignoring voltage drop, conductor resistance and mechanical flexibility on long or moving cable runs.

Frequently Asked Questions

What does AWG stand for?

American Wire Gauge. It is a conductor-size system in which smaller numbers mean larger nominal conductors.

Is 0.5 mm² the same as 20 AWG?

No. 20 AWG has a nominal solid-round area of about 0.518 mm², so it is close in area, not an automatically interchangeable cable specification.

Can 16 AWG replace 1.5 mm²?

Not when the requirement is a geometric area of at least 1.5 mm²: 16 AWG is about 1.31 mm². Check a larger available AWG and all electrical, terminal and certification requirements.

How many amps can 24 AWG carry?

There is no universal answer from gauge alone. Use the actual wire or cable product rating and the installation rules; do not copy a generic “2 A” value into a design.

Does stranded wire have a different AWG number?

AWG denotes the nominal conductor size, while stranding describes its construction. Individual strand diameters and overall conductor diameter differ from a solid conductor; use product data for resistance and finished dimensions.

Key Takeaway

Use the AWG chart to compare nominal geometry, the metric table to distinguish a familiar cross-reference from an equal-or-larger area, and condition-specific ampacity data to evaluate electrical suitability. For an industrial cable quotation, send TEBAOFLEX Cable your required standard, conductor size, load, installation, run length and operating environment so the proposed construction can be checked against the real duty.