AWG 33 wire size, resistance and weight calculator
AWG 33 is defined by the gauge formula, not by a table: the diameter is 0.127 mm times 92 raised to the power (36 - n) / 39. Everything else follows from that and the conductor resistivity.
A rough guide: 3 to 5 A/mm2 for chassis wiring, under 2 for long runs in conduit.
- Diameter
- 0.179 831
- Area in circular mils
- 0.050 125 8
- Resistance of that length
- 67.8764 ohm
- Resistance per kilometre
- 678.764 ohm/km
- Resistance per 1000 feet
- 206.887 ohm
- Weight of that length
- 0.022 757 6
- Current at the chosen density
- 0.10 A
- Turns per centimetre, close-wound
- 55.608
Show the working
- Length of wire = 100
- Conductor = 1.724e-8
- Conductor temperature = 20
- Conductor density = 8960
- Design current density = 4
- Diameter = 0.127 * 92^((36 - (33)) / 39) = 0.179 831
- diameter_in = 0.179 831 / 25.4 = 0.007 079 96
- Cross-sectional area = pi * 0.179 831^2 / 4 = 0.025 399 1
- Area in circular mils = 0.007 079 96^2 * 1000 = 0.050 125 8
- r_per_m_20 = 1.724e-8 / (0.025 399 1 * 1e-6) = 0.678 764
- r_per_m = 0.678 764 * (1 + 0.00393 * (20 - 20)) = 0.678 764
- Resistance of that length = 0.678 764 * 100 = 67.8764
- Resistance per kilometre = 0.678 764 * 1000 = 678.764
- Resistance per 1000 feet = 0.678 764 * 304.8 = 206.887
- Weight of that length = 0.025 399 1 * 1e-6 * 100 * 8960 = 0.022 757 6
- Current at the chosen density = 0.025 399 1 * 4 = 0.101 596
- Turns per centimetre, close-wound = 0.179 831 > 0 ? 10 / 0.179 831 : 0 = 55.6078
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- diameter in mm = 0.127 x 92^((36 - n)/39)
- area = pi d^2 / 4
- resistance = rho x length / area
- temperature correction: R(T) = R(20) x (1 + 0.00393 (T - 20)) for copper
The gauge formula is exact: 36 AWG is 0.127 mm and 0000 AWG is 11.684 mm, with 39 steps between them in a geometric progression of ratio 92^(1/39).
The current figure is a design rule of thumb from current density, not an ampacity rating. Real ampacity depends on insulation temperature rating, bundling, ambient temperature and the wiring code in force.
Aluminium conductors of the same gauge carry about 61% of the current of copper for the same heating.
Frequently asked
What is the diameter of AWG 33 wire?
It follows from the gauge definition: 0.127 mm x 92^((36 - n)/39). The calculator shows the result in millimetres and inches.
Why does the wire gauge number go down as the wire gets thicker?
The number counts drawing operations. Each pass through a die makes the wire thinner and adds one to the gauge, so a high number means a thin wire.