Nominal 6×6 → Actual 5½" × 5½"

What size is a 6×6, really?

A 6×6 is sold and labeled as 6 x 6, but it actually measures 5½" × 5½". The difference comes from milling and drying — the board starts closer to its named size, then shrinks as it's surfaced smooth and dried to standard moisture content.

DASHED = WHAT IT'S CALLED · SOLID = WHAT YOU GET

A 6×6 is actually 5½" × 5½" — not 6 x 6. Common uses include structural posts and heavy fence posts.

How many 6×6s do you need?

USES ACTUAL WIDTH, NOT NOMINAL

Boards to span a width

Calculates how many 6×6 boards, laid edge to edge, are needed to cover a given width — using the real 5½" width plus any gap you leave between boards.

Width to cover (ft)

Gap between boards (in)

Board feet

Uses the actual 5½" × 5½" dimensions to calculate true board feet for pricing or ordering.

Length (ft)

Quantity

6×6 vs. every other size

FULL REFERENCE CHART

Nominal Size	Actual Size	Actual (decimal)

Other sizes

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