Beam Load Calculator (Preliminary)

Estimate a preliminary elastic load limit for one idealised beam and load case. The result is the lower of a 0.6F_y bending-stress screen and a user-selected deflection-ratio screen; it is not a code design capacity.

Structural FEA

Analyse a beam in Structural FEA

Model continuous beams, frames, mixed supports, and multiple load cases. Review reactions, deflection, member forces, and elastic stress results on the model.

Point and distributed loads · Load combinations · 3D frames · Visual result diagrams

Try a Sample BeamStart From Scratch

How the Screening Limit Is Calculated

This calculator evaluates two simplified criteria:

• Bending-stress screen - elastic section stress reaches 0.6F_y
• Deflection screen - elastic deflection reaches the selected span ratio

The reported load is the lower of those values. That identifies the controlling calculator screen only; it does not establish that the member, restraints, connections, or load combinations are adequate.

Bending-Stress Screen

The maximum bending stress in a beam is:

Where M is the idealised elastic bending moment and S is the elastic section modulus. This page uses F_b = 0.6F_y as a transparent yielding screen, then back-calculates the corresponding load. It is not a substitute for the flexural resistance provisions of any design code.

For a simply supported beam with UDL, M_max = wL²/8, so the screened load is:

Deflection Screen

The maximum deflection is compared with the selected reference ratio (for example, L/360). The governing code, load component, and project criterion must be selected outside this calculator. Working backwards from the formula:

Rearranging for the corresponding screened load:

Input Values Explained

Section Modulus (S)

The elastic section modulus in mm³ or in³. For symmetric sections, S = I / (h/2) where h is the total depth. Look this up in section tables, or calculate it using our section properties calculator.

Yield Stress (F_y)

Enter the specified yield strength for the material and thickness being checked. Illustrative nominal values include:

• 250 MPa - one common metric structural-steel grade value
• 36 ksi - ASTM A36 minimum yield value for applicable shapes and thicknesses
• 50 ksi - a common US wide-flange nominal yield value

Verify the applicable product standard and thickness-dependent value. The calculator's 0.6F_y multiplier is only a simplified screen; ASD, LRFD, and other code methods require their own limit-state checks and factors.

Important Limitations

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