LVL Beam Span Calculator

An LVL span chart is the manufacturer's lookup table: find your beam depth, plies, and the tributary width of floor it carries, and read the maximum clear span — usually at an L/360 deflection limit under 40 psf live plus 10 psf dead load. A chart row for 11-7/8" LVL carrying a 12' tributary reads about 11'-6" for one ply; two plies push toward 14'-6"; three toward 16'-6". Three columns never change: depth (stiffness lives here), plies (capacity), tributary width (demand). This calculator reproduces the lookup from a reference planning table and scales plies on the deflection-governed n^(1/3) curve — then the verdict line tells you how much margin your target span actually has. Every result is a planning reference: the manufacturer chart for your exact series (1.9E, 2.0E, 2.1E) governs.

For one 11-7/8" LVL ply under a 40-10 residential floor at L/360, the planning span runs from about 13'-6" with an 8' tributary down to about 9'-11" at 16' tributary — the 12' tributary midpoint is roughly 11'-6". Doubling to two plies multiplies the deflection-governed span by 2^(1/3) = 1.26: about 14'-6" at 12' tributary. Three plies reach 1.44× ≈ 16'-6". A single 11-7/8" ply carrying a 20' span is outside the table — capacity and deflection both fail; the fixes are more plies, a deeper beam, or a mid-span post. These are reference planning values for a ~2.0E series: your manufacturer's 11-7/8" chart and local code govern the final call.

Every LVL span table runs on the same four variables. Depth: stiffness — deflection improves with the cube of depth, which is why 11-7/8" spans 35% farther than 9-1/2" at equal load (11.5 vs 8.5 ft at 12' tributary). Plies: capacity and stiffness scale together; because deflection usually governs, spans grow with the cube root of ply count, not linearly — 2 plies buy 26%, 3 buy 44%. Tributary width: the demand side — a beam with 12' joists landing on each side carries twice the load of one with 6' joists. Deflection limit: tables assume L/360 for floors; a garage beam under L/240 reads longer, a tile-floor beam at L/480 reads shorter. Read the chart's footnote line before the numbers — series (1.9E vs 2.0E), load case, and deflection limit move every value.

Four materials, four answers. LVL vs sawn 2x: a single 11-7/8" LVL ply out-spans a 2x10 (9.25" actual) by roughly 24% at the same load — 11.5 vs 9.3 ft at 12' tributary — and never twists a crown into the floor; the 2x wins only on price per foot and small openings. LVL vs I-joist: I-joists win the long-span floor bay (a 16" TJI reaches 22'+ as a joist), but LVL wins in beam duty — I-joists need web stiffeners, squash blocks, and engineered field details to concentrate beam loads; the two pair together, they don't compete. LVL vs glulam: glulam wins appearance work (exposed, curved, wide faces) and very long spans; LVL wins dimensional efficiency — 1-3/4" plies let you dial capacity in 1.75" steps. See the I-joist span calculator for the TJI side of that decision.

Run the calculator: enter depth, tributary width, and target span; the verdict tells you the ply count that clears the span with margin. The mechanics: 1 ply is the table value, 2 plies add 26% deflection-governed span (× 1.26), 3 plies 44% (× 1.44), 4 plies 59% (× 1.59). Worked example — a 16' clear span under a 12' tributary: 1 ply 11-7/8" reaches 11.5' (fail), 2 plies 14.5' (fail), 3 plies 16.5' (pass with 3%). The honest note: three plies at 3% margin is a pass by the table, but bearing, connectors, and crown tolerance eat real-world margin — if the verdict reads under 10%, step to the next depth before adding a fourth ply. Verify the final count against the manufacturer chart and local code.

LVL — laminated veneer lumber — is engineered wood: 3mm-ish veneers laid parallel, glued and pressed into billets up to 80' long, then sawn to standard depths (9-1/4" through 24") at 1-3/4" ply thickness. The manufacturing is the advantage: veneer grading disperses the knots that cap sawn lumber, so LVL carries roughly 2× the allowable bending stress of #2 sawn timber and holds dimension (seasoning checks don't move it). Costs and limits are real too: LVL is heavy (an 11-7/8" ply weighs about 5.5 lb/ft), it must be protected from weather, field notches are restricted to the manufacturer's rules (never notch the middle third of the span), and it needs proper end bearing. Verify fastening and bearing with the supplier's literature.

Minimum bearing is 3" on wood and 4" on steel or concrete for most series — but the honest number comes from the chart's bearing column, because capacity at the support drops as bearing shortens. Practical framing: 11-7/8" beams land on a double 2x4 post (3" net) or a 4x4 (3.5"); 16"+ depths want a 4x6 or an engineered post cap. Bearing length interacts with plies: a 3-ply beam concentrates three times the load into the same footprint, so the manufacturer's bearing table — not the 3" floor — decides. Bearing pads or steel plates spread load on concrete. One more field rule: shim compression at the top is a floor squeak factory — pack the gap with pairs of plates or an engineered post cap, not cedar shakes. Verify bearing with the manufacturer table and local code.

Yes — those are two of its most common jobs, and they size differently from floor beams. Headers over openings carry a wall's tributary (half the story weight above plus roof), and the sizing logic — opening width, wall thickness, load path — is the header size calculator's job. Structural ridge beams carry roof load down to posts at the gable walls; they size from span, pitch, and roof load, which the ridge beam calculator handles — and unlike a non-structural ridge board, an LVL ridge beam must land on continuous posts, not just the top plate. Both roles share one LVL-specific rule: the beam table that governs is the manufacturer's header/ridge chart, which prices capacity differently from the floor-beam chart on this page. Use this page's calculator for floor framing; follow the links above for the other two.

Yes, with the right section. A 20' clear span under a 12' tributary needs a 24" depth at 1 ply — the chart reads 24.67', clearing 20' with 19% margin — or a 20" depth at 3 plies (20.75' × 1.44 = 29.9', generous). The realistic menu, cheapest first: 24" deep 2-ply (extra margin at the cost of headroom), 20" deep 3-ply (shallower but wider), or an intermediate post that turns one 20' span into two 10' spans and drops the beam to 11-7/8" 2-ply — usually the cheapest solution when the floor plan allows a bearing point. Check headroom either way: a 24" beam under 8' finished ceilings consumes 25% of the clear height. Verify against the manufacturer's long-span chart.

L/360 is the residential floor default — a 16' beam may sag 0.53" under live load (192" ÷ 360). Three adjustments move it: tile or stone flooring wants L/480 (0.40" at 16'), rooms you want to feel solid can spec L/480 voluntarily, and garage or non-habitable framing often accepts L/240 (0.80"), which reads as longer spans in those tables. The calculator's reference table assumes L/360 and states it on the verdict line. The mechanics worth knowing: deflection governs most LVL floor beams — the capacity side usually has 15–25% headroom when deflection binds — which is why adding plies buys less span than intuition expects (the n^(1/3) curve) and why going deeper beats going wider every time. Verify the limit your inspector and finish floor require.