Wire Weight Calculator — Free Online Calculator
Calculate the weight of copper or aluminum wire per foot or meter for cable ordering and tray loading.
How to Use This Calculator
Select wire gauge and material, enter the total length needed.
The Formula Explained
Wire weight is proportional to its cross-sectional area and material density. Copper weighs about 3.3× more than aluminum for the same gauge.
Why Wire Weight Is More Than a Curiosity
Most electricians think about wire weight only once — when the spool hits the floor with a thud and they realize pulling 500 feet of 3/0 copper through conduit is going to hurt. But weight is a real engineering constraint that affects load calculations for cable trays, structural support for vertical risers, shipping costs on large projects, and pulling tension during installation. Commercial projects routinely specify maximum cable-tray loading in pounds per foot, and the wire weight is the dominant component.
Weight also drives the economics of copper vs aluminum on large feeders. A 1,000-foot run of 4/0 copper weighs about 1,280 pounds (just the conductor) and costs roughly USD 5,000 at 2026 prices. The same run in 4/0 aluminum weighs 400 pounds and costs about USD 1,200. That is not just a 4:1 price ratio — it is also a 3:1 shipping and handling ratio. On a utility-scale project with miles of feeders, the aluminum savings pay for an entire installation crew.
Worked Example: Vertical Riser in a 20-Story Building
A 20-story commercial building needs a 400-amp feeder rising from the basement electrical room to the 20th floor penthouse. That is roughly 220 feet of vertical rise. For 400A you need 600 kcmil copper (per 75°C table). 600 kcmil copper weighs about 1,870 pounds per 1,000 feet. Three conductors times 220 feet times 1.87 lb/ft = 1,234 pounds total hanging from the top support point.
NEC 300.19 requires conductor supports in vertical raceways to prevent the weight of the wire from damaging the conductor itself or its connections at the top. For 600 kcmil copper the required support interval is 60 feet — meaning you need support clamps (wedge plugs or cable grips) every 60 feet up the riser. Without proper support, the top termination becomes the sole load-bearing point and can literally tear the conductor out of its lug over time.
Worked Example: Cable Tray Loading Calculation
A commercial data center specifies a cable tray rated for 50 pounds per linear foot. The tray will carry 20 power circuits (each with 4 × 10 AWG THHN) plus 40 communication cables (each about 0.05 lb/ft). Power circuit weight: 20 × 4 × 0.040 lb/ft = 3.2 lb/ft. Communication: 40 × 0.05 = 2.0 lb/ft. Total: 5.2 lb/ft — well under the 50 lb limit.
But what if the data center scales up? Double the circuits to 40, each with 6 × 6 AWG copper. Weight becomes 40 × 6 × 0.126 lb/ft = 30.2 lb/ft for power, plus 2 lb/ft for comms = 32.2 lb/ft. Still under 50, but getting close. Add another 20% for fittings, tray weight, and future additions, and you are at the limit. This is why cable-tray loading calculations matter — they determine when you need a second tray or a heavier gauge tray.
Common Weight-Related Mistakes
1. Ignoring vertical support requirements. NEC 300.19 specifies support intervals for conductors in vertical raceways. Miss this on a multi-story riser and the top termination carries the full weight — a recipe for slow failure as the copper cold-flows out of the lug.
2. Underestimating pulling tension. Friction around each 90-degree bend roughly doubles the tension. A 500-foot pull with four bends can multiply input tension by 16x — enough to exceed the conductor pulling limit on large copper cables.
3. Loading cable trays without calculating. Trays have per-foot load ratings. Add conductors willy-nilly over years of retrofits and you can exceed structural capacity without realizing it.
4. Forgetting insulation weight. Bare copper weight is only about 75% of insulated THHN weight, and SER or USE-2 can add 30-40%. Calculate with the insulated weight, not the bare conductor weight.
5. Mixing units. North American tables use pounds per 1,000 feet. European data uses kg per km. Converting: 1 lb/1000ft = 1.488 kg/km. Do not assume one or the other without checking.
Practical Weight Reference for Common Sizes
For rough field estimation, keep these numbers handy. Bare copper: 14 AWG is 12.4 lb/1000ft, 12 AWG is 19.8 lb, 10 AWG is 31.4 lb, 8 AWG is 50 lb, 6 AWG is 79.5 lb, 4 AWG is 126 lb, 2 AWG is 201 lb, 1/0 is 320 lb, 4/0 is 641 lb, and 500 kcmil is 1,544 lb. THHN insulation adds 12-18% depending on gauge.
Bare aluminum weighs about 30% of copper per foot for the same AWG. After upsizing two AWG sizes for ampacity equivalence, aluminum still comes out to about 50% of copper weight. For a 200-amp feeder, that is the difference between 320 lb of copper and 160 lb of aluminum on a 200-foot run — one person can carry the aluminum up the stairs, two people and a dolly for the copper.
NEC and Industry References
NEC 300.19 covers conductor support in vertical raceways with support interval requirements by conductor size. NEC 392 covers cable trays including loading calculations and fill requirements. ICEA P-45-482 and NEMA WC 70 cover conductor pulling tension limits and sidewall pressure calculations. The rule of thumb of 0.008 times cmil for copper pulling tension comes from these standards and is why large copper pulls require lubrication and carefully planned bend counts.
For shipping and material planning, manufacturer catalogs (Southwire, Encore, General Cable) publish exact weights per 1,000 feet for every wire size and insulation type. Use those for bid-quality estimates; the calculator above is for design-phase sanity checks.
Wire weight: planning the pull, ordering reels, sizing supports
Wire is heavy. A 1000-foot reel of 4/0 copper THHN weighs about 640 pounds; the same length in aluminum, 245 pounds. Knowing the weight matters when you order reels (delivery, hoisting), plan cable trays (deflection limits), pull long conduit runs (tension on the pulling rope), or just lift the spool off the truck.
The calculator gives the conductor weight per length and total weight for a given run. It does not include the weight of the conductor jacket and insulation, which adds 15-30 percent for THHN/THWN and more for armored cable types like MC.
The formula and what it does
For copper: weight (lb per 1000 ft) is approximately 0.000308 x CM. For aluminum, 0.000094 x CM. So 1/0 copper (105,600 CM): 0.000308 x 105,600 = 32.5 lb per 1000 ft. The full reel of 1000 ft weighs 325 lb of conductor, more with insulation and the reel itself.
Worked example
Scenario: 600 ft pull of three 250 kcmil aluminum XHHW for a 400 A feeder, plus a 4/0 aluminum neutral and 1/0 copper ground.
250 kcmil aluminum: 0.000094 x 250,000 = 23.5 lb/1000 ft per conductor. Three of them, 600 ft: 3 x 23.5 x 0.6 = 42.3 lb. 4/0 aluminum (211,600 CM): 0.000094 x 211,600 x 0.6 = 11.9 lb. 1/0 copper (105,600 CM): 0.000308 x 105,600 x 0.6 = 19.5 lb. Total conductor weight, 73.7 lb. With insulation (about 25 percent uplift) and conduit fittings, expect to load about 100 lb of cable plus the reel weight. A two-person pull, with a tugger if there is much bend in the conduit.
Common mistakes to avoid
Underestimating reel logistics. A full reel of 4/0 copper is over 600 lb and needs forklift or hoist handling. Smaller jobs are sometimes done with paid stub reels (200 ft cut lengths) to skip the equipment.
Ignoring pulling tension. IEEE 525 caps copper conductor tension at 0.008 lb per CM, so 100,000 CM (1/0) can handle 800 lb of pulling tension before stretching. Long, bendy conduit runs exceed this faster than you would expect, especially in cold weather when the jacket is stiff.
Frequently asked questions
How much does the insulation add to wire weight?
THHN/THWN-2 adds about 15-25 percent to bare copper weight depending on AWG. MC cable with armor adds 50-100 percent. Manufacturers publish exact per-foot weights on the cut-sheet; Southwire and Encore Wire datasheets are the standard references.
Why is aluminum so much lighter than copper?
Aluminum density is about one-third of copper (0.098 vs 0.323 lb per cubic inch). Even after sizing up one to two AWG for equivalent ampacity, aluminum feeders typically weigh 40-50 percent of the copper alternative. That is why service entrances on commercial jobs are almost always aluminum.
Does the weight matter for box fill?
Not directly, but NEC 314.16 counts conductor volume for box fill. Indirectly, conductor weight pulls on splices and terminals if the box is loaded with long unsupported runs above it.
How do I plan cable tray loading?
NEMA VE 1 sets tray weight limits. Calculate the total cable weight per linear foot, multiply by the span, and verify against the tray rating. Heavy commercial feeders sometimes exceed standard tray ratings and need extra supports every few feet.
What is the heaviest wire I can pull by hand?
About 1/0 copper in straight runs under 100 ft. Beyond that you want a hand tugger or motorized puller. Pulling lubricant on conduit interior cuts friction by half and is essential on anything 2 AWG or larger.
How heavy is a typical 200 A service entrance?
2/0 aluminum SE cable for 200 A service runs about 30 lb per 100 ft including jacket. A typical 30 ft mast-to-meter run is about 9 lb, easily handled by one person.