Beam Load Capacity Calculator
Calculate maximum load for wood and LVL beams. Estimate safe span and deflection.
🏗️ Construction📐 Max Load = (Fb × S × 8) / L
Beam span (feet)
Beam width (inches)
Beam depth (inches)
Material
Please enter valid values.
Formula & Reference
| Variable | Formula | Units |
|---|---|---|
| Beam Load Capacity Calculator | Max Load = (Fb × S × 8) / L | lbs UDL |
Step-by-Step Examples
Example 1
LVL Floor Beam
12 ft, 3.5 in wide, 11.25 deep, LVL.
- S = 74.1 in³ | W ≈ 9,879 lbs UDL
✓ ~9,879 lbs UDL
Example 2
Douglas Fir
16 ft, 1.5 wide, 9.25 deep, DF #2.
- W ≈ 1,018 lbs UDL
✓ ~1,018 lbs
Example 3
Any span over 20 ft
Needs structural engineering.
- This tool is for estimation only
- Consult a structural engineer
✓ Get engineer
Real-World Applications
Builders
Estimate beam sizing for framing projects.
Estimators
Quick structural reference for bidding.
Architecture Students
Learn beam load calculations.
Contractors
Verify sizing before engineering review.
Common Mistakes to Avoid
⚠️
Not using a structural engineer
These are estimates only. All structural work requires a licensed structural engineer.
⚠️
Not checking local codes
Minimum beam sizes vary by jurisdiction and load type.
Frequently Asked Questions
How are floor beams sized? ▾
By span, tributary width, and design loads (dead + live load).
LVL vs solid lumber? ▾
LVL is stronger, more consistent, resists warping. Preferred for long spans.
When do I need an engineer? ▾
Any structural change, wall removal, span over 20 ft, or added floor loads.