Wire Gauge Chart (AWG to mm²)

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Printable AWG to mm² wire gauge chart with conductor diameter, cross-section, resistance per km and typical ampacity — plus an instant AWG ↔ mm² converter.

Inputs

Conversion

Convert

AWG size

Optional

Cable length (one way) (m)

Used for the loop resistance figure

How to use this calculator: Wire Gauge Chart (AWG to mm²)

Printable AWG to mm² wire gauge chart with conductor diameter, cross-section, resistance per km and typical ampacity — plus an instant AWG ↔ mm² converter. The example below is calculated by this page's real engine from the displayed inputs.

1Confirm that the Wire Gauge Chart (AWG to mm²) matches the quantity or design check you need.
2Enter Cable length (one way) using the units printed beside each field.
3Select the applicable Convert and AWG size options; these choices change the calculation method or factors.
4Calculate, then follow the substituted equations in the worked example and compare the result with any stated limit.
5Read the assumptions, warnings and cited references before using the result for a financial, medical or engineering decision.

Input guide and example values

Use values from the same measurement basis and time period. Conditional fields appear only when the related option is selected.

Input	Example value	Why it matters
Convert	AWG → mm²	Select the option that matches the real installation or scenario.
AWG size	12 AWG	Select the option that matches the real installation or scenario.
Cable length (one way)	10 m	Used for the loop resistance figure

Formula inputs & variables for Wire Gauge Chart (AWG to mm²)

These are the named quantities used by this calculator. When the source formula does not define a mathematical symbol, OneCalcApp keeps the real input label instead of inventing one.

Variable / input	Unit	Meaning in this calculation
Convert	—	Select the option that matches the real installation or scenario.
AWG size	—	Select the option that matches the real installation or scenario.
Cross-section	mm²	Measured or known cross-section used by the calculation engine.
Cable length (one way)	m	Used for the loop resistance figure

Formula, derivation and worked example

American Wire Gauge is a reverse-logarithmic scale: the bigger the number, the thinner the wire, and every 6 gauges roughly halves or doubles the cross-section. 10 AWG is 5.26 mm², 4 AWG is 21.2 mm², and going three steps up (10 → 7) doubles the copper. The rest of the world specifies conductors directly in mm², so the two systems never line up exactly — 2.5 mm² sits between 13 and 14 AWG and is normally sold against 14 AWG. Use the table below to translate a spec, check what a cable drum actually contains, or work out the resistance of a run before you buy it.

Diameter (mm) = 0.127 × 92^((36 − n) / 39)

Area (mm²) = π/4 × diameter²

Resistance (Ω/km) = 17.24 / area in mm² (copper at 20 °C)

Substitution steps

1. Area
π/4 × d²
= 3.31 mm²
2. Resistance
17.24 / area
= 5.208 Ω/km
3. Loop
2 × length × Ω/km
= 0.1042 Ω

Computed example results

Cross-section: 3.31 mm²; 12 AWG
Conductor diameter: 2.053 mm
Resistance (copper, 20 °C): 5.208 Ω/km
Typical current rating: 25 A; indicative — derate for heat and grouping
Nearest metric cable to buy: 4 mm²; sold against 12 AWG, ≈ 26 A
Loop resistance: 104.2 mΩ; 20 m of conductor
Aluminium equivalent: 8.542 Ω/km; same size in aluminium

Understanding the result

Read the main result together with supporting checks, assumptions, limits and intermediate values.

For a manual check, repeat the first equation, confirm the units and change one input at a time.

Assumptions and calculation scope

Cross-section is assumed to be entered in mm²; converting from another unit before entry avoids changing the numerical meaning of the calculation.
Convert is assumed to match the real case. Choosing a different available option can change the method, factor or interpretation used by this calculator.
Wire Gauge Chart (AWG to mm²) applies the displayed Diameter (mm) = 0.127 × 92^((36 − n) / 39) relationship to the entered electrical inputs. Factors that are not exposed as inputs or stated assumptions are outside this calculator's calculation scope.

Common mistakes when using Wire Gauge Chart (AWG to mm²)

Do not mix units for Cable length (one way) (m). A unit mismatch changes the input magnitude even when the typed number looks reasonable.
Do not leave Convert on the default choice unless that choice matches the real scenario; the selected option can change the calculation path or factor.
Do not replace the displayed Diameter (mm) = 0.127 × 92^((36 − n) / 39) relationship with a different convention without also changing the underlying assumptions; compare like-for-like methods when checking the result.
Do not treat Cross-section = 3.31 mm² from the worked example as a universal answer. It belongs to the displayed example inputs and must be recalculated for the actual case.

When the Wire Gauge Chart (AWG to mm²) is useful

Wire Gauge Chart (AWG to mm²) is designed for cases where Convert, AWG size, Cable length (one way) are known and you need Cross-section, Conductor diameter, Resistance (copper, 20 °C). The page keeps the live calculator, calculation method and worked example together so the result can be checked instead of treated as a black-box number.

Use the calculator for the scope described by its inputs and notes. The displayed method is Diameter (mm) = 0.127 × 92^((36 − n) / 39). If the real project or decision needs factors that are not represented here, treat the result as an estimate and add the missing checks separately.

Convert and AWG size: what changes the answer

The worked example uses Convert = AWG → mm², AWG size = 12 AWG, Cable length (one way) = 10 m. With those values, Cross-section is 3.31 mm². Changing an input should be interpreted according to that field's unit, range, option and hint rather than by the number alone.

For this calculator, the main input roles are: Convert: Select the option that matches the real installation or scenario. Available choices include AWG → mm², mm² → AWG. AWG size: Select the option that matches the real installation or scenario. Available choices include 4/0 (0000) AWG, 3/0 (000) AWG, 2/0 (00) AWG, 1/0 (0) AWG. Cable length (one way) (m): Used for the loop resistance figure

How to sanity-check a Wire Gauge Chart (AWG to mm²) result

Start by confirming the entered values and units, then compare the substituted working with the displayed formula or calculation steps. Pay particular attention to Cross-section, because it is the first worked-example output shown by the live engine.

Finally, compare the result with the assumptions, warnings and related calculators on this page. A nearby calculator can be useful as a cross-check when it measures the same workflow from a different input or output direction.

Next logical calculator

Continue with Wire Size Calculator (AWG & mm²)

Wire Size Calculator (AWG & mm²) is directly connected from Wire Gauge Chart (AWG to mm²) as a source-defined continuation or comparison.

Open Wire Size Calculator (AWG & mm²)

Formula

Diameter (mm) = 0.127 × 92^((36 − n) / 39)
Area (mm²) = π/4 × diameter²
Resistance (Ω/km) = 17.24 / area in mm² (copper at 20 °C)

Engineering notes

Ampacity figures are indicative for insulated copper conductors around 30 °C ambient; always derate for grouping, insulation rating, ambient temperature and installation method.
Aluminium carries roughly 78% of the copper current for the same size, and has about 1.64× the resistance.
AWG covers solid conductors; stranded cable of the same AWG has a slightly larger overall diameter but the same copper area.

AWG to mm² wire gauge chart (copper, 20 °C)

Diameter and area are for solid copper. Resistance is Ω per km of conductor; a circuit has two conductors, so a 10 m run has 20 m of conductor. Current ratings are typical insulated-conductor values, not a substitute for the wiring code.

AWG	mm²	Diameter (mm)	Resistance (Ω/km)	Typical current (A)
4/0 (0000)	107.2	11.684	0.161	230
3/0 (000)	85	10.404	0.203	200
2/0 (00)	67.4	9.266	0.256	175
1/0 (0)	53.5	8.252	0.322	150
1	42.4	7.348	0.407	130
2	33.6	6.544	0.513	115
4	21.2	5.189	0.815	85
6	13.3	4.115	1.296	65
8	8.37	3.264	2.061	50
10	5.26	2.588	3.277	35
12	3.31	2.053	5.211	25
14	2.08	1.628	8.286	20
16	1.31	1.291	13.17	15
18	0.82	1.024	20.95	10
20	0.52	0.812	33.31	7
22	0.33	0.644	52.96	5
24	0.2	0.511	84.22	4

Common metric ↔ AWG pairs

1.0 mm² ≈ 17 AWG · 1.5 mm² ≈ 16 AWG · 2.5 mm² ≈ 14 AWG · 4 mm² ≈ 12 AWG · 6 mm² ≈ 10 AWG · 10 mm² ≈ 8 AWG · 16 mm² ≈ 6 AWG · 25 mm² ≈ 4 AWG · 35 mm² ≈ 2 AWG · 50 mm² ≈ 1/0 AWG · 70 mm² ≈ 2/0 AWG · 95 mm² ≈ 3/0 AWG · 120 mm² ≈ 4/0 AWG.

SWG is a different scale

British Standard Wire Gauge (SWG) numbers do not match AWG. 10 SWG is 3.25 mm diameter (8.3 mm²) while 10 AWG is 2.59 mm (5.26 mm²) — check which gauge a supplier means before ordering.

Every 3 gauges doubles the copper

Because the scale is logarithmic, dropping three AWG numbers doubles the area and halves the resistance; dropping ten numbers multiplies the area by ten.

12V Wire Size Chart (12V, 24V & 48V)

Amps against run length for low-voltage DC circuits — RV, marine, solar and battery wiring.

Worked example

1A spec calls for 12 AWG. From the chart that is 3.31 mm², 2.053 mm in diameter, 5.211 Ω/km.
2A 10 m run has 20 m of conductor → 20 × 5.211/1000 = 0.104 Ω loop resistance.
3At 15 A that costs 15 × 0.104 = 1.56 V of drop.

Tips

When a metric size falls between two gauges, buy the larger conductor (the smaller AWG number).
For long runs, size on voltage drop rather than the ampacity column — it almost always governs.

Frequently asked questions

What is 12 AWG in mm²?

12 AWG is 3.31 mm² with a 2.053 mm conductor diameter. In practice it is supplied against 4 mm² metric cable.

What is 2.5 mm² in AWG?

2.5 mm² is closest to 14 AWG (2.08 mm²). It is slightly larger, so 14 AWG applications are safely covered.

Is a higher AWG number thicker or thinner?

Thinner. AWG is reverse-numbered: 24 AWG is a thin signal wire, 4/0 AWG is a 107 mm² service conductor.

How many amps can 10 AWG carry?

Around 30–35 A for insulated copper in typical conditions, but the wiring code value depends on insulation rating, ambient temperature and how many cables run together.

How do I convert AWG to mm?

Diameter in mm = 0.127 × 92^((36 − n)/39). For 10 AWG: 0.127 × 92^(26/39) = 2.588 mm.

Is AWG the same as SWG?

No. SWG is the older British scale and the same number gives a different diameter — 10 SWG is 3.25 mm against 2.59 mm for 10 AWG.

What inputs does the Wire Gauge Chart (AWG to mm²) use?

It uses Convert, AWG size, and Cable length (one way). Follow the unit printed for each field and choose any selectable option to match the real scenario.

What does the Wire Gauge Chart (AWG to mm²) calculate?

It calculates Cross-section, Conductor diameter, Resistance (copper, 20 °C), Typical current rating, Nearest metric cable to buy, Loop resistance, and Aluminium equivalent. With the displayed default inputs, Cross-section is 3.31 mm².

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