About

Hardware inventory management often relies on weight rather than individual counting. This tool estimates the total weight of a batch of screws based on their specifications. The calculation utilizes the material density (e.g., Carbon Steel at 7.85 g/cm³) and volumetric approximation of the shank and head. While exact weights vary by manufacturer due to tolerance differences in ANSI B18.6.3 standards, this calculator provides a reliable inventory estimate (typically ±10%).

Accurate weight estimation prevents stock discrepancies and aids in shipping logistics where weight limits apply. It supports common configurations including Machine Screws, Wood Screws, and Sheet Metal Screws across varying materials like Stainless Steel, Brass, and Aluminum.

Formulas

The weight estimation relies on summing the volume of the cylindrical shank and the approximated head volume, then multiplying by the material density.

Weight ≈ (V_head + V_shank) × Density × Count

Where the Shank Volume is calculated as a cylinder:

V_shank = π × (d2)² × L

Head volumes are derived from lookup coefficients based on the specific ANSI standard for the selected Head Type (e.g., Pan, Flat, Hex).

Reference Data

Material	Density (g/cm³)	Common Usage	Corrosion Resistance
Carbon Steel	7.85	General Construction, Wood Screws	Low (requires plating)
Stainless Steel (304)	8.00	Outdoor, Marine, Decking	High
Stainless Steel (316)	7.98	Saltwater Environments	Very High
Brass	8.73	Decorative, Plumbing, Electrical	Medium
Aluminum (6061)	2.70	Lightweight Applications, Siding	High
Nylon 6/6	1.15	Electronics, Insulating	High (Chemical)
Silicon Bronze	8.53	Marine Woodworking	High
Titanium (Grade 5)	4.43	Aerospace, High Performance	Excellent

Frequently Asked Questions

Manufacturing tolerances for screw heads and thread pitches vary between brands. A ±10% range accounts for these slight differences in metal volume and plating thickness (e.g., Zinc vs. Black Phosphate).

No. This tool calculates the weight of the screw body only. Nuts and washers must be calculated separately as their volume ratios differ significantly.

Standard coatings (Zinc, Black Oxide) add negligible weight. For thick coatings like Ceramic or Hot Dip Galvanized, consider adding 2-3% to the final estimate.

Yes. If you know the total weight of a box, you can divide it by the "Single Unit Weight" provided by this tool to estimate the quantity.

Rolled threads (common in most screws) use the same volume of material as the blank shank. Cut threads remove material. This calculator assumes standard rolled thread production, which preserves the material mass.