Beam Span Chart

Built-up beams (multiple 2x boards nailed together) carry loads across openings. These are rough maximum spans for a beam supporting one floor level — the real span depends heavily on the load width it carries.

Built-up beam Approx. max span
(2) 2×8 about 6 ft
(2) 2×10 about 7 ft
(2) 2×12 about 8 ft
(3) 2×10 about 9 ft
(3) 2×12 about 10 ft
Load width drives span. A beam carrying a wide tributary area spans far less than these. For anything structural, size the beam with an engineer or official span table.

Estimates for planning only — confirm load-bearing beams with a professional.

See the Joist Span Chart and the Header Span Chart.

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The calculators and tools on Formula Factory are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. Formula Factory makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.