Nominal 2×10 → Actual 1½" × 9¼"

What size is a 2×10, really?

Q: What size is a 2×10, really?

A nominal 2×10 actually measures 1½" × 9¼". 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 2×10 is sold and labeled as 2×10, but it actually measures 1½" × 9¼". 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 2×10 is actually 1½" × 9¼" — not 2×10.

What a 2×10 is actually used for

Floor joists (longer spans), stair stringers, headers

Good to know before you buy

A common joist size for standard residential spans, but always verify against your local code's span tables for your actual spacing and load, not just habit.

How many 2×10s do you need?

USES ACTUAL WIDTH, NOT NOMINAL

Boards to span a width

Calculates how many 2×10 boards, laid edge to edge, are needed to cover a given width — using the real 9¼" width plus any gap you leave between boards.

Width to cover (ft)

Gap between boards (in)

Board feet

Uses the actual 1½" × 9¼" dimensions to calculate true board feet for pricing or ordering.

Length (ft)

Quantity

2×10 vs. every other size

FULL REFERENCE CHART

Nominal Size	Actual Size	Actual (decimal)

Other sizes

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