Why is 16 inches on center the standard?

Because 16 divides evenly into 48 and 96 inches, so 4x8 sheets of drywall or sheathing break on a stud every time. 24 in O.C. also divides evenly and uses fewer studs.

What does O.C. mean on a plan?

O.C. means on center. A note like 2x4 studs at 16" O.C. tells you the spacing of framing members measured center to center. You will also see it on joists, rafters and fence posts.

What does 16" on center mean?

On-center (O.C.) spacing is the distance from the center of one framing member to the center of the next. 16 in O.C. is the standard for wall studs, and 24 in O.C. is also used. Measuring center to center keeps the edges of 4x8 sheets landing on framing.

Formula

Studs = wall length in inches / spacing, plus 1, then add for corners, openings and intersections

Worked example

A 20 ft wall framed at 16 in O.C.

1.20 ft x 12 = 240 inches
2.240 / 16 = 15
3.15 + 1 = 16 studs

16 studs before adding corners, openings and intersections.

Measure it in MetreMate

Measure each wall run in linear feet with the Measure tool, then apply your spacing, and use Count to mark corners and openings that need extra studs.

See the Measure Tools feature

Related terms

Frequently asked questions

Back to the construction takeoff glossary

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