Steel Surface Area Calculator
Theoretical geometric surface area and the estimated area to be coated, separated for open and hollow sections.
Result – SHS 120x120x6
Theoretical geometric area
External surface area2.756m²
Internal surface area2.530m²
Total geometric surface area5.287m²
Practical area to be treated
Estimated coating area2.756m²
External area per metre0.459m²/m
External area per tonne22.14m²/t
- Hollow section: external coating only (typical for paint systems).
- End faces excluded.
- Allowance applied: 0.0 %.
Method & assumptions
External area = Pext × L × N ; Internal area = Pint × L × N ; Coating area = (Pext + k·Pint) × L × N × (1 + allowance) + end areas
Pext / Pint = external / internal coated perimeter (m²/m), k = 1 if the inside is coated (e.g. hot-dip galvanizing) else 0
Theoretical geometric area. Practical treated area depends on the coating system: hollow sections are normally painted externally only, while hot-dip galvanizing coats inside and outside. Add allowances for connections, stiffeners and cleats.