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About This Wood Beam Calculator
Design wood beams per NDS 2024 (National Design Specification for Wood Construction). This free calculator checks bending, shear, bearing, and deflection with full adjustment factor transparency.
What It Checks
- Bending — fb = M/S ≤ F’b per NDS 3.3.1
- Shear — fv = 1.5V/(bd) ≤ F’v per NDS 3.4.2
- Bearing — fc⊥ = R/(b×lb) ≤ F’c⊥×Cb per NDS 3.10.2
- Deflection — Δ ≤ L/360 (live) and L/240 (total) per IBC Table 1604.3
NDS Adjustment Factors
Every adjusted design value shows the full factor chain: CD (load duration), CM (wet service), Ct (temperature), CL (beam stability), CF (size factor), Cr (repetitive member), Cb (bearing area). No black boxes.
Auto-Size Comparison
The calculator shows all available dimensional lumber sizes with utilization ratios for bending, shear, and deflection — so you can instantly see which members work and which is the most efficient choice.
Free version: Douglas Fir-Larch #2, dimensional lumber. Upgrade to Pro for all species, glulam, LVL, and branded PDF reports.
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