Conversor AWG a mm²: calculadora y tabla (incluye kcmil a mm²)

This guide explains precise AWG to mm conversions, calculator logic, and Kcmil equivalences for engineers.

Includes tables, formulas, examples, normative references, and calculation steps for practical implementation in multiple contexts.

AWG / kcmil to mm converter — diameter and cross-sectional area calculator

Input type AWG (American Wire Gauge) kcmil (thousands of circular mils) Diameter (mm) Area (mm²) AWG preset 14 AWG 12 AWG 10 AWG 8 AWG 6 AWG 4 AWG 2 AWG 1 AWG 1/0 (0 AWG) 2/0 3/0 4/0 Custom

AWG number (gauge)

kcmil preset 250 kcmil 350 kcmil 500 kcmil 750 kcmil 1000 kcmil Custom kcmil (kcmil)

Diameter (mm)

Area (mm²)

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Primary output unit Diameter (mm) Area (mm²) kcmil Diameter (mils) Decimals

Show detailed breakdown Yes No kcmil conversion constant

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Formulas used

AWG diameter (inches): d_in = 0.005 * 92^((36 - n) / 39), where n = AWG number (0 for 1/0, -1 for 2/0, etc.).

Diameter (mm): d_mm = d_in * 25.4.

Area (mm²): A = π * (d_mm)² / 4.

kcmil ↔ mm²: A(mm²) = kcmil * C, where C is the kcmil conversion constant (default 0.5067075 mm² per kcmil).

kcmil = A(mm²) / C.

Common AWG	Diameter (mm)	Area (mm²)	kcmil
14 AWG	1.63	2.08	4.10
12 AWG	2.05	3.31	6.53
10 AWG	2.59	5.26	10.38
4/0 (0000)	11.684	107.22	211.59

FAQ

Q: Does the calculator assume solid or stranded conductor? A: Results are geometric and represent conductor equivalent circular area/diameter; stranded constructions may have slightly different outer diameters but identical cross-sectional area if same metal cross-section is used.

Q: Which constant is used for kcmil to mm² conversion? A: Default constant is 0.5067075 mm² per kcmil (1 circular mil = 0.0005067075 mm²).

AWG, kcmil and metric parameters: definitions, scope and common uses

American Wire Gauge (AWG) is the U.S. standard for round, solid conductor diameters. Kcmil (kilo circular mil) expresses cross-sectional area using the circular-mil convention. Metric systems use diameter in millimetres (mm) and cross-sectional area in square millimetres (mm²), which are required by IEC and many international specifications.

This section establishes the physical meanings, practical roles in specification and the reason for accurate, normative conversions when designing power systems.

Fundamental conversion relationships and essential formulas

AWG diameter formula (empirical)

The AWG diameter for gauge number n (n is integer, where AWG 0 is n = 0, 1 is n = 1, and 0000 is n = -3) in inches is given by:

d_in = 0.005 × 92^{(36 − n) / 39}

To convert to millimetres:

Where:

• d_in = diameter in inches
• d_mm = diameter in millimetres
• n = AWG gauge number (use 0, 00, etc., by mapping 0 → 0, 00 → −1, 000 → −2, 0000 → −3 or use tables)

Typical check values: AWG 10 → d_in ≈ 0.1019 in → d_mm ≈ 2.588 mm. AWG 4 → d_mm ≈ 5.189 mm.

Circular mils, kcmil and metric area

Definitions and conversions:

circular_mils = (d_in × 1000)²

area_mm2 = π × (d_mm / 2)²

Direct empirical conversion factor:

1 circular mil = 0.000506707 mm²

Therefore:

and

Variable definitions:

• circular_mils = diameter in mils² (1 mil = 0.001 in)
• kcmil = circular mils / 1000
• area_mm2 = cross-sectional area in square millimetres (metric)

Typical: 1 kcmil ≈ 0.506707 mm²; therefore 750 kcmil ≈ 750 × 0.506707 ≈ 380.03 mm².

Electrical resistance and voltage drop formulas

Basic DC or low-frequency line resistance for uniform conductor:

Where:

• R = resistance in ohms (Ω)
• ρ = resistivity in ohm-meters (Ω·m) at a reference temperature
• L = conductor length in metres (m)
• A = cross-sectional area in square metres (m²)

Unit conversions for area: area_mm2 → A (m²) by A = area_mm2 × 1e-6.

Typical resistivities at 20 °C:

• Copper: ρ ≈ 1.724 × 10⁻⁸ Ω·m (typical annealed copper; some tables use 1.68–1.72×10⁻⁸)
• Aluminium: ρ ≈ 2.826 × 10⁻⁸ Ω·m

Temperature correction approximate (for copper):

Where α ≈ 0.00393 /°C for copper (linear approximation).

Voltage drop (single-phase) and power loss

Voltage drop (magnitude) in single-phase circuits:

V_drop = I × R_total = I × R × 2 (if return conductor has same R) = I × 2 × R

Power loss (I²R):

P_loss = I² × R_total

Variables:

• I = current in amperes (A)
• R_total = round-trip resistance for the circuit in ohms (Ω)

Comprehensive AWG to mm and kcmil table (common sizes)

kcmil to mm² quick reference table (common large sizes)

Step-by-step calculation procedure (practical algorithm for a converter/calculator)

1. Input: AWG number (or diameter or kcmil). If AWG is supplied, compute d_in using AWG diameter formula.
2. Convert d_in to d_mm: d_mm = d_in × 25.4.
3. Compute circular_mils = (d_in × 1000)².
4. Compute kcmil = circular_mils / 1000 and/or area_mm2 = circular_mils × 0.000506707.
5. For resistance: choose conductor material and temperature. Convert area_mm2 to A (m²) by dividing by 1e6. Use R = ρ × L / A.
6. For voltage drop: compute round-trip R_total and V_drop = I × R_total. Optionally compute percentage drop = (V_drop / V_system) × 100%.

Important implementation notes

• AWG sizing is defined for solid round conductors. Stranded conductor effective diameter and AC skin/stranding factors affect resistance. Use strand-equivalent area for DC resistance, and use correction factors for AC (skin and proximity) at higher frequencies.
• Resistivity varies with purity, temper and temperature. Use manufacturer data for high-precision tasks.
• Where standards require, consult IEC 60228, IEEE, or national codes (e.g., NFPA 70/NEC) for allowable ampacity and installation factors — cross-section conversion alone is not sufficient for ampacity selection.

Detailed worked examples

Example 1 — AWG 10 conductor: conversion, DC resistance and voltage drop for a 30 m single-phase run carrying 30 A

Given: AWG 10 conductor, length one-way L = 30 m, current I = 30 A, material = copper at 20 °C. System voltage V_system = 230 V (single-phase).

Step 1 — geometry and area:

• From table: AWG 10 diameter d_mm = 2.588 mm.
• Area (from table) area_mm2 = 5.261 mm². Convert to m²: A = 5.261 × 10⁻⁶ m².

Step 2 — DC resistance per length:

• Use ρ_cu = 1.724 × 10⁻⁸ Ω·m.
• R_one_way = ρ × L / A = 1.724×10⁻⁸ × 30 / (5.261×10⁻⁶)

Compute numeric:

Round-trip resistance R_total = 2 × R_one_way ≈ 0.1966 Ω.

Step 3 — voltage drop and power loss:

• V_drop = I × R_total = 30 × 0.1966 ≈ 5.898 V.
• Percentage voltage drop = (5.898 / 230) × 100% ≈ 2.56%.
• Power loss P_loss = I² × R_total = 30² × 0.1966 ≈ 177.0 W.

Interpretation:

• Voltage drop ≈ 2.56% is acceptable under many installations (≤3% recommended for branch circuits), but check local code and continuous loading rules.
• Loss of ~177 W is dissipated as heat; consider thermal ratings for insulation and bundling effects.

Example 2 — Convert 750 kcmil to metric area and calculate DC resistance for a 100 m aluminum feeder carrying 600 A

Given: conductor size = 750 kcmil, length one-way L = 100 m, current I = 600 A, material = aluminium (typical utility/conduit feeder), temperature 20 °C.

Step 1 — area conversion:

• Use conversion: area_mm2 = kcmil × 0.506707.
• area_mm2 = 750 × 0.506707 = 380.03025 mm².
• Convert to m²: A = 380.03025 × 10⁻⁶ = 3.8003025 × 10⁻⁴ m².

Step 2 — DC resistance per length:

• Use ρ_Al = 2.826 × 10⁻⁸ Ω·m (typical).
• R_one_way = ρ × L / A = 2.826×10⁻⁸ × 100 / 3.8003025×10⁻⁴

Compute numeric:

Round-trip R_total = 2 × 0.007437 ≈ 0.014874 Ω.

Step 3 — voltage drop and power loss:

• V_drop = I × R_total = 600 × 0.014874 ≈ 8.924 V.
• Percentage voltage drop (assume 480 V 3-phase line-to-line; for single-phase equivalence use line voltage) — for demonstration assume 480 V: % drop ≈ (8.924 / 480) × 100% ≈ 1.86%.
• P_loss = I² × R_total = 600² × 0.014874 ≈ 5,352.0 W (≈5.35 kW).

Interpretation:

• For a heavy feeder length of 100 m carrying 600 A, voltage drop ≈ 1.86% at 480 V is within many recommended limits; check three-phase distribution correction (line-to-line vs line-to-neutral) and code requirements.
• Power dissipation ~5.35 kW is significant and requires thermal management; check conductor ampacity derating for installation configuration.

Considerations for stranded conductors, AC frequency and derating

Stranded conductors: the nominal cross-sectional area (mm²) remains the determinant for DC resistance calculations, but practical resistance depends on fill factor, compaction, and metallurgy. Manufacturer datasheets provide DC resistance per unit length for specific strand constructions at a reference temperature.

AC effects (skin effect and proximity effect) increase effective resistance with frequency and conductor size. For low-voltage power distribution (50/60 Hz) and typical power conductor diameters (below several tens of mm), AC increase is modest but non-negligible for very large conductors and parallel runs. Use IEC/IEEE guidelines and Campbell diagrams or AC resistance correction factors when needed.

Standards, normative references and authoritative resources

• IEC 60228 — Conductors of insulated cables (classifies nominal cross-sectional areas and conductor types) — https://www.iec.ch/
• NIST (resistivity and physical constants) — https://www.nist.gov/
• IEEE Standards Collection — for conductors, cable ampacity and installation practices — https://standards.ieee.org/
• NFPA 70 (NEC) — U.S. National Electrical Code, ampacity and installation rules — https://www.nfpa.org/ — see ampacity tables and correction factors
• American Wire Gauge (AWG) reference — comprehensive technical reference: https://en.wikipedia.org/wiki/American_wire_gauge (useful summary; consult standards for final acceptance)
• Circular mil explanation and conversions — https://en.wikipedia.org/wiki/Circular_mil

Practical recommendations for engineers and implementers

• Always cross-check AWG ↔ mm² conversions against manufacturer data sheets and national/regulatory tables for ampacity selection.
• For stranded conductors, use manufacturer DC resistance per unit length as the authoritative value rather than geometric idealizations.
• When designing for voltage-sensitive equipment, calculate voltage drop for the worst-case loading and ensure compliance with code limits (commonly 3% for branch circuits, 5% combined for feeders and branch circuits, subject to local codes).
• Include installation factors: number of conductors in conduit, ambient temperature, grouping, insulation type — these alter ampacity and, sometimes, allowable voltage drop.
• Document assumptions: temperature of reference resistivity, conductor material, length type (one-way vs round-trip), and whether areas are nominal or measured.

Calculator implementation checklist (for software developers)

1. Accept input types: AWG, diameter (in or mm), circular mils, kcmil, mm².
2. Normalize input to a canonical internal representation (e.g., area_mm2).
3. Apply accurate conversion constants (1 circular mil = 0.000506707 mm²).
4. Offer material library with resistivity vs temperature and α (temperature coefficient) values.
5. Provide option for stranded conductor correction factors, skin/proximity corrections for AC frequencies above low tens of Hz.
6. Output: diameter (mm), area (mm²), circular mils, kcmil, resistance per metre (Ω/m), resistance for specified lengths, voltage drop, percent drop, and power loss.
7. Include normative links, unit tests with known gauge values and round-trip checks for backward and forward conversions.

Summary of key numeric factors and quick formulas (for reference)

• AWG diameter formula: d_in = 0.005 × 92^{(36 − n)/39}
• Diameter conversion: d_mm = d_in × 25.4
• Circular mils: c_mils = (d_in × 1000)²
• kcmil to mm²: area_mm2 = kcmil × 0.506707
• Resistance: R = ρ × L / A (A in m²)
• Voltage drop: V_drop = I × R_total (R_total = round-trip resistance)

References and authoritative links (repeated for quick access)

• IEC 60228 — Conductors of insulated cables: https://www.iec.ch/
• NIST — physical constants and reference data: https://www.nist.gov/
• IEEE standards: https://standards.ieee.org/
• NFPA 70 (NEC): https://www.nfpa.org/
• AWG technical description: https://en.wikipedia.org/wiki/American_wire_gauge
• Circular mils explanation: https://en.wikipedia.org/wiki/Circular_mil

Note: the numeric tables and conversion constants used above follow widely accepted engineering references. For final procurement or safety-critical designs, confirm with manufacturer datasheets and local regulatory tables (e.g., IEC/EN or NEC) and consider environmental and installation-specific deratings.