What is it?
The Beam Load Calculator checks how much a beam bends and how hard it is stressed under a load. It shows the maximum bending moment, shear force and deflection (sag), and compares the sag with a common safe limit.
Who is it for?
Engineering students, and anyone learning how beams bend; real structures need an engineer.
How to use it
- Choose the Beam support: Simply supported (both ends) or Cantilever (fixed at one end).
- Choose the Load: One point load (centre / free end) or Spread evenly along the beam (UDL), and enter it with the Span.
- For deflection, enter the Elastic modulus (E) (GPa: steel 200, aluminium 69, concrete ~25, timber ~10) and the Moment of inertia (I) from section tables.
Limits of the tool
Standard formulas for a straight beam of one material. Beam self-weight is not added. For any real building work, have a structural engineer check the design. Reinforced concrete, composite sections, continuous beams and dynamic loads need proper design to the building code.
Reading deflection
Deflection limits like span ÷ 250 or span ÷ 360 keep floors from feeling bouncy and stop cracks in plaster and tiles. A beam can be strong enough but still bend too much.
Moment of inertia comes from the section shape: for a rectangle, I = b × d³ ÷ 12, so making a beam deeper helps far more than making it wider.
Errors and how to fix them
- “Enter the span (more than 0)”: type the beam length between supports.
- “Enter E (more than 0)” or “Enter I (more than 0)”: E is the material’s stiffness and I is the beam section’s stiffness, both from the material or section table. Without them the sag can’t be worked out.
- Use it for learning and rough checks only: a real beam must be designed and checked by a structural engineer.
Open the tool: Beam Load Calculator
Still stuck?
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Questions, or an error not listed here?
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