Bolt Weight & Dimensions Calculator
Estimate assembly weight for structural heavy hex or standard hex bolts — including nuts and washers — and pull head, nut, and washer dimensions for detailing and takeoff.
Bolt Assembly Calculator
Technical Specifications
Bolt Assembly Weight for Takeoffs
Hardware weight is easy to miss on a tonnage estimate, yet hundreds of 3/4″ A325 assemblies add real pounds to shipping and erection. This calculator builds each assembly from shank weight per inch plus head, nut, and washer components, then scales by quantity for bid and shipping takeoffs.
How to use this calculator
- Choose A325/A490 (heavy hex structural) or A307 (standard hex) — head and nut weights differ.
- Set diameter and bolt length under the head, then toggle nuts/washers and per-bolt counts (two washers are common on slip-critical joints).
- Enter total quantity to see lot weight. Use the dimension panel to confirm wrench clearance and washer OD on congested connections.
Heavy hex vs standard hex
Structural bolts follow ASME B18.2.6 with wider flats and F436 hardened washers. A307 machine bolts use finished hex hardware and USS washers — lighter, but not interchangeable on structural joints that call for A325/F3125. Mixing patterns on a BOM is a frequent estimating error when the schedule lists “3/4×2-1/2 bolt” without grade.
FAQ
Is length under-head or overall?
Under-head length, matching how structural bolts are ordered. Do not add head height to the length field.
Are weights exact mill values?
They are estimating weights from published component data. Use them for takeoff and freight; certified weights for paid steel may differ slightly by manufacturer.
Should galvanized hardware use a different weight?
Coating adds a small percentage. For rough takeoffs the bare-steel values are fine; for precise shipping of large lots, ask your fastener supplier for coated assembly weights.
Why show nut and washer dimensions?
Detailers need flats and washer OD for edge distance, cope clearance, and impact-wrench access — especially on short end distances and nested angles.
Related guide: Plate and Bolt Weight Takeoffs for Paint and Shipping