Wood Beam Size Calculator
Required section modulus and a suggested rectangular size for a timber beam.
Timber stresses span 3× between species and grades — verify the grade stamp. Also check shear (1.5V/bh) and bearing at supports; deep narrow beams need lateral restraint.
Formula
Wood Beam Size Calculator is a free wood beam size for structural engineers, fabricators and site engineers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Wood Beam Size Calculator
Required section modulus and a suggested rectangular size for a timber beam. The calculation implements S_req = M/F_b; h = √(6S/b) (IS 883; NDS for Wood Construction). Timber stresses span 3× between species and grades — verify the grade stamp. Also check shear (1.5V/bh) and bearing at supports; deep narrow beams need lateral restraint.
How to use Wood Beam Size Calculator
- 1Enter Max bending moment in kN·m.
- 2Enter Allowable bending stress in MPa (Sal/teak ~12–16 · SPF/deodar ~7–10 MPa).
- 3Enter Chosen breadth in mm.
- 4Read Required S, Required depth at chosen breadth instantly — no submit button needed.
- 5Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Wood Beam Size Calculator?
- ✓Implements the standard formula — S_req = M/F_b; h = √(6S/b)
- ✓Reference cited on-page: IS 883; NDS for Wood Construction
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Live worked example: the substitution recomputes from your numbers
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Wood Beam Size Calculator use?+
It computes S_req = M/F_b; h = √(6S/b), per IS 883; NDS for Wood Construction. The formula is displayed under the result along with a worked example substituted with your own inputs.
What should I keep in mind when using this calculator?+
Timber stresses span 3× between species and grades — verify the grade stamp. Also check shear (1.5V/bh) and bearing at supports; deep narrow beams need lateral restraint.
Can I use this for real structural design?+
It implements the exact textbook/code formula cited below the result and is ideal for sizing, checking and learning. Final designs should be verified by a qualified engineer against the full code with all load cases.
Is the Wood Beam Size Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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