Weights for hex bolts, stud bolts and nuts in carbon and alloy steel, metric and inch series. Add items to build a list and get the total for a shipment, in kilograms and pounds.
Theoretical weight from nominal dimensions. Actual weight normally runs 2–3% higher because of the under-head radius, chamfers and thread tolerances. Use it for costing, packing and freight estimates; for contract quantities confirm against a weighed sample.
ISO 4014 partly threaded hex bolts, carbon steel at 7.85 g/cm³.
Weight is the sum of the volumes, multiplied by the material density:
0.866 × s² × k, where s is the width across flats and k the height. For a nut the threaded hole is deducted.d₂ = d − 0.6495 × p. The thread crests and roots roughly balance around the pitch diameter, so it represents the metal actually present. Nominal diameter overstates the weight; minor diameter understates it.Thread length. Metric partly threaded bolts follow ISO 888: 2d + 6 up to 125 mm, 2d + 12 over 125 to 200 mm, 2d + 25 above 200 mm. IS 3757 structural bolts use their own shorter tabulated thread lengths. Inch bolts follow 2d + ¼" up to 6" long and 2d + ½" above.
Inch threads. UNC coarse to 1". Above 1" the calculator uses the 8 UN series, which is standard practice for large structural and flange bolting — not UNC.