Structural Wood Designer — Beams, Headers, Posts, Studs & Bracing
Engineering-based residential wood sizing. Floor/deck joists, rafters, beams and girders, window & door headers, posts & columns, and bearing-wall studs — checked against NDS allowable values for bending, shear, deflection, and column buckling. Plus an IRC wind-bracing guide.
Planning aid — not a stamped design
These tools use NDS reference values and standard simplifying assumptions (simple spans, uniform loads, concentric axial loads). They do not replace a licensed engineer for point loads, cantilevers, continuous/multi-span members, combined bending+axial, or lateral design. Always confirm with your building department, and use an engineer where failure risks life safety.
Clear span between supports.
2x10, Douglas Fir-Larch #2
✓ PASS at 14 ft span
Max allowable span
15.6 ft
Governing check
Bending
80% utilized
Live deflection at 14 ft
0.29"
limit 0.47"
Total load
67 lb/ft
50 psf × 1.33 ft
Smallest member that works for this scenario
2x10 in Douglas Fir-Larch #2
Max span by size — Douglas Fir-Larch #2, 1-ply, 16" o.c., 40+10 psf
| Member (1-ply) | Max span | Governs |
|---|---|---|
| 2x6 | 9.7 ft | Live deflection (L/360) |
| 2x8 | 12.8 ft | Live deflection (L/360) |
| 2x10 | 15.6 ft | Bending |
| 2x12 | 18.1 ft | Bending |
| 1.75x9.25 LVL | 16.9 ft | Bending |
| 1.75x11.875 LVL | 20.6 ft | Bending |
| 1.75x14 LVL | 23.1 ft | Bending |
| 1.75x16 LVL | 26.4 ft | Bending |
| 1.75x18 LVL | 29.7 ft | Bending |
How to Use This Calculator
Pick a scenario tab: Beams & Joists for spans carrying area loads; Headers for openings above windows and doors (guided load takedown); Posts & Columns for axial supports; Wall Studs for bearing walls and cripples; Wind Bracing for lateral/braced-wall guidance. Each tool checks the real engineering limits and recommends the smallest member that works.
Formula Used
Bending fb = M/S (M = wL²/8); shear fv = 1.5V/A (V = wL/2); deflection Δ = 5wL⁴/(384·E·I). Columns: Fc′ = Fc·CD·CF·Cp where Cp is the NDS stability factor and Fce = 0.822·Emin/(le/d)². All allowables adjusted per NDS (load duration CD, size factor CF, repetitive Cr).
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Disclaimer
This calculator is for estimation purposes only. Results may vary based on local conditions, materials, and building codes. Always consult a licensed professional before making decisions based on these calculations. MyContractorTools is not responsible for any errors or omissions.