The black diamond (sometimes a black triangle or arrow) on a tape measure is a stud layout aid, and it has a very specific meaning.

What it means

The black diamond marks 19.2 inches on center.

Why 19.2 inches matters

• 19.2 inches equals five studs spaced evenly across an 8-foot (96-inch) wall.

• This spacing is sometimes used in construction as an alternative to the standard 16-inch spacing.

• It allows builders to:

  • Use fewer studs

  • Save on lumber and cost

  • Still meet building code requirements in certain designs

When it’s used

• Primarily in advanced framing (also called optimum value engineering)

• Often seen in commercial construction or energy-efficient residential builds

• Less common in typical homes, which usually use 16-inch or 24-inch spacing