Calculate the weight of steel wire rope from its diameter, construction and length, in lb and kg, with weight per foot and per meter for common ropes.

The nominal size, measured across the widest point of the rope. Enter fractions as decimals: 1/2 in is 0.5 and 3/8 in is 0.375.

The numbers are strands x wires per strand, as printed on the reel tag or certificate. Other ropes: choose Custom and enter the catalog weight.

Several pieces (optional)
For several equal lengths, such as the legs of a sling. Blank counts one piece.

Calculator Functions

The calculator estimates the weight of a length of steel wire rope in pounds and kilograms, along with its weight per foot and per meter.

FunctionUse it whenYou enter
Wire rope weightYou know the rope’s size and construction and need its weight for a lift plan, a sling, a reel or shippingRope diameter, construction and length

The diameter can be in inches or millimeters and the length in feet or meters. Eight common constructions are built in. For any other rope, choose Custom weight per foot or meter and enter the figure from the maker’s catalog. The optional Number of pieces multiplies the result for several equal lengths, such as the legs of a sling. To find how much load the rope can carry, use the SWL of Wire Rope Calculator.

Wire Rope Weight Formulas

W = k × d² × L
WRope weight (lb)
kWeight per foot of a 1 in rope of the same construction (lb/ft)
dNominal rope diameter (in)
LRope length (ft)

Rope tables list an approximate weight per foot for each size, and those weights rise with the square of the diameter: a 6×19 class fiber core rope is listed at 0.40 lb/ft for 1/2 in and 1.60 lb/ft for 1 in [1]. One number for each construction, k, therefore reproduces its table. A steel core adds about 10% to the weight of a fiber core rope of the same size [1].

Constructionk (lb/ft at 1 in)Metric k (kg/m at 1 mm)
6×19 class, steel core (IWRC) [1] [3]1.760.00406
6×19 class, fiber core [1] [3]1.600.00369
6×37 class, steel core (IWRC) [2]1.850.00427
6×37 class, fiber core [2]1.680.00388
Stainless 6×19 or 6×37, steel core [2]1.850.00427
8×19 class, fiber core [2]1.570.00362
18×7 rotation resistant, fiber core [2]1.730.00399
7×19 small cable, up to 3/8 in [2]1.800.00415

For 500 ft of 1/2 in 6×19 class steel core rope, the weight per foot is 1.76 × 0.5² = 0.44 lb/ft, so the rope weighs 0.44 × 500 = 220 lb, or 99.8 kg.

Metric sizes

W = km × d² × L

With the metric k from the table, d in millimeters and L in meters, W is in kilograms. A 12 mm 6×19 class steel core rope weighs 0.00406 × 12² = 0.585 kg/m, so 100 m of it weighs 58.5 kg. The metric k is the same table weight converted: k × 1.48816 ÷ 25.4².

Limits of This Estimate

  • The table weights are approximate, and real rope differs by a few percent between makers and strand patterns. These estimates are based on the best available data and estimations. For a critical lift, use the weight on the rope’s certificate or in the maker’s catalog.
  • The result is for bare rope. Thimbles, sleeves, sockets, hooks and the reel are not included, so a finished sling weighs more.
  • The 7×19 small cable value is an average. Listed weights for 1/8 to 3/8 in sizes work out to between 1.73 and 1.86 times d² [2].
  • Ropes outside these classes, such as compacted strand or plastic-filled ropes, are not covered by the built-in values. Use the custom option with the maker’s weight per foot or meter.

Sources

  1. U.S. Department of Commerce, National Bureau of Standards, Commercial Standard CS154E-49, Wire Rope, Table 7: weights of 6×19 class fiber core rope and the 10% addition for a steel core
  2. U.S. General Services Administration, Federal Specification RR-W-410G, Wire Rope and Strand, Tables VII to XL: weights of 6×37 class, stainless, 8×19, 18×7 and 7×19 small ropes
  3. Unirope, Class 6×19 IWRC and Fiber Core: a rope maker’s current weights for 6×19 class rope with steel and fiber cores