Nominal 2×8 → Actual 1½" × 7¼"

What size is a 2×8, really?

Q: What size is a 2×8, really?

A nominal 2×8 actually measures 1½" × 7¼". 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.

A 2×8 is sold and labeled as 2×8, but it actually measures 1½" × 7¼". 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 2×8 is actually 1½" × 7¼" — not 2×8.

What a 2×8 is actually used for

Floor joists (shorter spans), header beams

Good to know before you buy

Span tables use the actual 7¼" depth, not the nominal 8" — check your species and grade against local code span tables before spacing joists.

How many 2×8s do you need?

USES ACTUAL WIDTH, NOT NOMINAL

Boards to span a width

Calculates how many 2×8 boards, laid edge to edge, are needed to cover a given width — using the real 7¼" width plus any gap you leave between boards.

Width to cover (ft)

Gap between boards (in)

Board feet

Uses the actual 1½" × 7¼" dimensions to calculate true board feet for pricing or ordering.

Length (ft)

Quantity

2×8 vs. every other size

FULL REFERENCE CHART

Nominal Size	Actual Size	Actual (decimal)

Other sizes

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