Copper Wire Weight Calculator

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What to calculate: Chooses the solve direction: mass from a known length, or length from a known mass.

Wire gauge (AWG): A standard US wire size system for round conductors. Bigger AWG numbers mean thinner wire [1].

Conductor diameter: The bare copper wire diameter, not the outside size of insulation.

Cross-sectional area used: The area the calculator actually used after converting from AWG or diameter when needed.

Equivalent diameter: The round-wire diameter that matches the used area. This helps compare different input methods.

Mass per unit length: How much bare copper mass there is for each foot, meter, or inch of wire.

Copper volume: The total volume of copper implied by the wire size and result.

Density: Mass per unit volume [2]. In this calculator, density connects size and length to mass.

Mistake: Entering the full insulated cable outside diameter into Conductor diameter (selected diameter unit) .
Fix: Use the bare copper conductor diameter only, or switch to Wire gauge (AWG) or Cross-sectional area (selected area unit) if that is the size you know.

Mistake: Picking Diameter unit as inches but typing a millimeter value into Conductor diameter (selected diameter unit) .
Fix: Make the number and the unit match before calculating.

Mistake: Typing a value into Wire length (selected length unit) when What to calculate is set to Length from mass and expecting that length to drive the result.
Fix: In that mode, enter Wire mass (selected mass unit) instead. Length is the output.

Mistake: Using Cross-sectional area (selected area unit) in circular mils while Area unit is left on square millimeters.
Fix: Change Area unit to match the number you have, then check Cross-sectional area used to confirm the conversion.

Mistake: Choosing Custom density under Density source but leaving Copper density (selected density unit) blank or in the wrong unit.
Fix: Enter a positive density value and set the correct Density unit . If you want normal copper, switch back to standard density.

Mistake: Treating Wire mass as total cable weight including insulation, plating, or strand gaps.
Fix: Read Wire mass and Mass per unit length as bare copper conductor values only unless you add those extras separately.

• Results are for bare copper conductor only. Insulation, jackets, plating, strand voids, and reel or spool weight are not included.
• AWG mode assumes standard round copper wire geometry. Non-round conductors should be entered with Cross-sectional area instead.
• Diameter mode assumes the conductor is round. If the actual conductor is compacted, stranded, square, or rectangular, use the true metal area when possible.
• Custom density changes mass and length results directly. If the alloy or temperature differs from standard copper, your real value may differ.
• Very small wires or very large lengths can produce tiny or large numbers, so display rounding may hide small differences even though internal math keeps full precision.
• The calculator uses one consistent density for the whole wire and does not model manufacturing tolerances or dimensional variation along the length.
• Mass and weight are often used loosely in everyday talk, but this tool computes mass from density. Any force-based weight depends on local gravity and is not the main output here.

Core method

The calculator first converts the chosen wire size into cross-sectional area, then uses volume and density to find mass or reverse-solves for length. Density is mass per unit volume [2].

m = ρ (density) x V (volume)

V = A (cross-sectional area) x L (length)

L = m / (ρ x A)

How each size mode is handled

If you enter Wire gauge (AWG), the calculator converts AWG to bare conductor diameter in inches using the standard AWG relationship [1], then converts that diameter to area.

d_in = 0.005 x 92^((36 - AWG) / 39)

A = π x d^2 / 4

If you enter Conductor diameter, the calculator converts the diameter to meters and then computes area for a round wire.

A = π x d^2 / 4

If you enter Cross-sectional area, that value is converted directly into square meters for the internal math.

Units used internally

Internal calculations use meters, square meters, cubic meters, kilograms, and kilograms per cubic meter. The final outputs are converted back to your selected mass and length units. The default standard copper density is 8960 kg/m3.

Extra outputs

Cross-sectional area used is always shown in mm2 so you can verify the actual size used. Equivalent diameter is shown in mm for easy comparison. Mass per unit length is found by dividing total mass by total length after both are expressed in the selected output units. Copper volume is shown in cm3.

mass per unit length = total mass / total length

Mini example

Suppose you choose Mass from length, set Wire size input method to AWG, pick 12 AWG, and enter 100 ft. The calculator converts 12 AWG to a diameter of about 2.053 mm, which gives an area of about 3.309 mm2. It then multiplies area by length to get volume and multiplies volume by density to get mass. The result is about 0.989 lb, and the mass per unit length is about 0.00989 lb/ft.

Practical notes

If your result looks too high, the most common cause is entering insulated cable diameter instead of bare conductor diameter. If your result looks too low or too high by a large factor, check the selected unit on the active size field and compare the derived area and diameter with what you expected.