Which inch interval is typically clearly marked in red on carpentry rulers?

Which inch interval is typically clearly marked in red on carpentry rulers?

• A. 12
• B. 16
• C. 20
• D. 18

Answer: (B)

Red markings on carpentry rulers indicate 16-inch intervals, which align with the standard on-center spacing used for wall studs in framing. This makes it quick to locate studs behind walls, estimate distances, and place fasteners without counting every inch. The 16-inch spacing works well because it divides evenly into halves, quarters, and eighths, and it matches common sheet sizes and traditional framing practices. On many tapes, you’ll see red marks at 16, 32, 48 inches, and so on, providing a fast reference during layout. So, the interval typically clearly marked in red is 16 inches.