United StatesNDS 2024 (LRFD)
Design and verify wood beams to NDS 2024 LRFD, bending, shear, bearing, and three deflection limits, each shown with the governing NDS adjustment factors and code reference. Load reactions at each support link directly to connected column and footing calculations so changes propagate automatically through the full load path. Supports simple and continuous spans, multi-ply beams, flitch plate composite beams, and inclined configurations.
The easy to use online Calcs.com Wood Beam LRFD Calculator to NDS 2024 enables you to do quick and powerful design and analysis for simple and continuous wood beams, with unlimited supports and loads. Choose from our library of thousands of common wood sections, or create your own and get instant results with our easy to understand traffic light checks for moment, deflection, and shear. The calculator also supports flitch plates.
Method & scope
Calculation method
The Wood Beam (LRFD, NDS 2024) calculator checks sawn lumber, glulam, LVL, I-joist, and flitch plate beams against the Load and Resistance Factor Design provisions of the 2024 National Design Specification for Wood Construction. For each ASCE 7 load combination, the calculator resolves factored demands and compares them against factored resistances adjusted through the NDS 2024 LRFD framework.LRFD adjustment framework
NDS LRFD converts reference design values, tabulated on an ASD basis in the NDS Supplement, into the LRFD resistance space using the format conversion factor K_F. Each adjusted resistance is then multiplied by the applicable resistance factor φ and the time effect factor λ, which accounts for the duration of the governing load:- λ = 0.8 for occupancy live loads
- λ = 1.0 for snow (short duration) and impact
- λ = 1.25 for wind and seismic
Bending check (NDS 2024, Cl. 2.3)
utilization = M_u / φM_n ≤ 1.0 The calculator evaluates all ASCE 7 load combinations, identifies the one producing the maximum factored moment M_u, and compares it against the factored moment resistance φM_n. For beams without continuous bracing, beam stability factor C_L is computed from the effective slenderness ratio R_B and governs when lateral-torsional buckling is critical.Shear check
utilization = V_u / φV_n ≤ 1.0 Factored shear V_u is taken conservatively at the face of support rather than at distance d as permitted by code. The factored shear resistance φV_n applies the shear resistance factor and the full suite of adjustment factors relevant to the shear reference design value F_v.Bearing check
utilization = R_u / φR_n ≤ 1.0 Governing bearing demand R_u (maximum factored vertical reaction at any support) is compared against the factored bearing resistance φR_n. Minimum required bearing lengths at end and interior supports are output separately. Bearing at point loads is not checked per the calculator assumptions.Deflection checks
Three independent deflection limits are verified using unfactored (service-level) loads:- Live/short-term deflection: δ_ST ≤ Δ_ST,max (default span/360, user-adjustable)
- Long-term deflection: δ_LT ≤ Δ_LT,max (default span/240, accounts for creep under sustained loads)
- Simplified DL+(LL or SL) deflection: δ_D+(L|S) ≤ Δ_D+(L|S),max
Reactions and load linking
At each support, the calculator outputs maximum factored vertical and horizontal reactions (R_u,vertical and R_u,horizontal). These reactions can be linked directly to connected wood column or footing calculations in the same project, so downstream members update automatically when beam loading or geometry changes.How to use it
1
Open the calculator
Open it from Run calc in the About this calculator panel above. To start from a typical setup, choose one of the presets listed there.
2
Enter your inputs
Work through the input sections from top to bottom. Click any input label to see its reference explanation, clause, conditions and assumptions. See Checks, References, Conditions and Assumptions.
3
Review the results and export
Check the utilization of each governing check in the summary, then export a PDF report. See Views and Export.
Available presets
Each preset opens the calculator with a typical setup already entered.Common questions
What design standard does this calculator use?
What design standard does this calculator use?
Load and Resistance Factor Design (LRFD) per NDS 2024. Factored demands are compared against factored resistances using NDS phi-factors, format conversion factors K_F, and time effect factors λ sourced from the 2024 NDS Supplement.
What are the key inputs?
What are the key inputs?
Span configuration (simple, continuous, or cantilever), wood species and grade, section size and number of plies, support conditions, lateral bracing for LTB, and applied loads by type (dead, live, roof live, snow, wind). Reference design values are loaded automatically from the NDS 2024 Supplement.
What checks and outputs does it produce?
What checks and outputs does it produce?
Factored bending (M_u ≤ φM_n per NDS 2024 Cl. 2.3), shear (V_u ≤ φV_n), bearing (R_u ≤ φR_n), and three deflection limits: live/short-term, long-term, and simplified DL+(LL or SL). Each check shows the governing load combination and utilization ratio.
Does it support multi-ply and flitch plate beams?
Does it support multi-ply and flitch plate beams?
Yes. The calculator handles multi-ply sawn lumber and glulam beams, composite flitch plate beams (steel plates sandwiched between wood), I-joists, and inclined members. For flitch plates, shear and bearing are conservatively assigned to the wood component and the combined section is checked for bending.
When should I use LRFD NDS 2024 instead of ASD?
When should I use LRFD NDS 2024 instead of ASD?
Use LRFD when your load combinations follow ASCE 7 factored format, or when wind or seismic loads govern the design. ASD remains more common for routine gravity-dominated residential and light commercial work. The choice typically follows your firm’s standard practice and what your AHJ accepts.
Does this calculator support load linking with column and footing calculations?
Does this calculator support load linking with column and footing calculations?
Yes. Vertical and horizontal reactions at each beam support can be linked directly to connected wood column or footing calculations in the same project. When span lengths, section sizes, or loads change, all linked calculations update automatically, no manual re-entry.
Next steps
Design a Deck Beam
Part 2 of the Deck Design Series: design a deck beam to NDS 2024, ASD or LRFD, with the Wood Beam: Deck Beam preset.
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Part 1 of the Deck Design Series: design a deck joist to NDS 2024, ASD or LRFD, with the Wood Beam: Deck Joist preset.
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Use the US Wood Beam calculator: size and grade selection, supports, load inputs, and reading moment, shear and deflection results.
US Wood Beam - Interpreting & Optimizing Results
Read the four wood beam checks (bending, shear, deflection and bearing) in Calcs.com and find ways to optimize the design.
US Wood Beam - Validation Examples (ASD & LRFD)
Validation examples for wood beams (ASD and LRFD) to NDS 2018: Calcs.com moment, shear and deflection results compared with textbook results.
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