LVL Beam Span Calculator

Tributary Width

The width of floor or roof area that loads onto the beam, measured as half the joist span on each side. If joists span 12 ft on both sides, the tributary width is 12 ft (not 24). The calculator assumes uniformly distributed loads — point loads from columns or concentrated loads are outside scope.

Section Selection (Width × Depth)

Choose from guide-valid width and depth combinations. Widths correspond to the number of plies (1-ply = 1¾″, 2-ply = 3½″, etc.). Built-up (multi-ply) members require field fastening — connection design for built-up members is not checked by this calculator. Depths are actual (not nominal) dimensions.

Live vs. Total Deflection

Live-load deflection (e.g., L/360) controls floor stiffness under occupancy loads. Total-load deflection (e.g., L/240) controls long-term sag under the full dead-plus-live load. Both limits are checked independently; the more restrictive one governs.

Bearing

LVL beams need adequate bearing at each support. If an available bearing length is supplied, a perpendicular-compression check is performed. Support-material capacity (e.g., the stud pack or foundation below) remains outside scope.

Bracing

All results assume adequate lateral bracing at supports and along the compression edge. Unbraced beams may fail at loads well below calculated values due to lateral-torsional buckling. Compression-edge lateral support and support bracing are required assumptions, not calculated checks.

Connection Design

Built-up-member fastening, end connections, and hanger selection are not evaluated. Multi-ply beams require proper nailing or bolting per the manufacturer's connection schedule.

Lateral-Torsional Buckling

Unbraced compression edges can cause beams to twist and buckle at loads significantly below the calculated bending capacity. Lateral bracing is assumed but not verified.

Support Members

Columns, stud packs, foundation walls, and other support members are not checked. Verify that supporting elements can carry the end reactions.

Point Loads & Non-Uniform Loads

Only uniformly distributed gravity loads are considered. Point loads from columns, headers, or equipment, seismic/lateral loads, and fire design are excluded.

Exterior / Wet-Service

All products are evaluated for dry-use conditions only. Exterior, wet-service, or treated applications are outside scope.

Upgrade depth before adding plies for deflection

Deflection is proportional to 1/d³. Going from 9¼″ to 14″ depth increases stiffness by ~3.5×. Adding plies helps bending and shear — if deflection governs, increase depth first.

Use the span table for quick comparison

The span table shows every guide-valid width × depth combination at once. Green cells meet your entered span; red cells do not.

Check bearing length

LVL beams need adequate bearing at supports — typically 1.5″ minimum for residential, more for heavy loads. Enter an optional bearing length to check perpendicular-compression capacity.

Versa-Lam 7″ load distribution

Per the Boise Cascade guide, 7″-wide Versa-Lam members must be top-loaded or loaded from both sides. One-sided loading of 7″ members is not covered by this calculator's uniformly distributed load assumption. Verify your loading configuration against the manufacturer's installation requirements.

Related calculators

For joist sizing, use the joist span calculator. For roof dimensions, see the roof size calculator. For steel beam weight, try the I-beam weight calculator.