If a fillet weld spans the full length of the joint, which statement about the length dimension is true?

• A. No length dimension is needed.
• B. A length dimension must be specified.
• C. The length equals the joint width.
• D. The length equals twice the weld size.

Answer: (A)

When a fillet weld runs the full length of the joint, the length is defined by the joint itself, so no separate length dimension is needed. The weld size (leg length) and any required throat are the primary dimensions you specify, and the continuous extent is already conveyed by showing the joint length on the drawing. Adding a distinct length callout would be redundant.

If you did need to specify length, it would only apply to partial welds, not a full-length weld. The idea that the length should equal the joint width or twice the weld size doesn’t align with how fillet welds are sized and referenced—the length follows the seam, while width and size describe the cross-section of the weld, not its overall extent.