Steel Weight Tolerances: ASTM and ISO Sizing Standards

In structural construction, steel sections can vary slightly from their nominal dimensions. Manufacturers operate under standards (like ASTM and ISO) that define the allowable variations in weight and thickness.

ASTM Sizing Tolerances

Under ASTM A6, structural shapes can vary in weight by up to 2.5% from their nominal values. For steel plates, thickness can vary based on the width of the plate. This means that a batch of steel may weigh slightly more or less than the nominal calculation.

Bidding Considerations

When bidding on large projects, engineers must factor these tolerances into their calculations to ensure they stay within structural limits and avoid logistics delays due to weight limits.

Determine nominal weights using our length to weight steel calculator. For plate calculations, read our guide on how to calculate plate steel weight.