Construction Calculator - Materials and Specs

Beam Load Calculator

Estimate simple beam reactions and bending moment for early planning.

Reviewed: August 26, 2026

Calculate Beam Load

For the Beam Load Calculator, enter beam span, uniform load, and center point load. It returns symmetric end reactions and maximum moment for a simply supported beam with a full-span uniform load and centered point load.

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Formula and input notes

End reaction = (uniform load × span + center point load) ÷ 2; maximum moment = wL² ÷ 8 + PL ÷ 4

InputPractical note
Beam spanUse the clear or effective simply supported span intended by the analysis model; support and bearing geometry can change that definition.
Uniform loadEnter a line load distributed over the full span in pounds per foot, including self-weight if the load case requires it.
Center point loadThis load is assumed to act at midspan. A point load elsewhere produces different reactions and moment.
Beam Load Calculator measurement plan showing Beam span feet, Uniform load lb / foot, Center point load lb

Worked beam load example

Beam Load Calculator example: Each support reaction is (40 × 9.7 + 0) ÷ 2 = 194 lb. Maximum moment is 40 × 9.7² ÷ 8 + 0 × 9.7 ÷ 4 = 470 lb-ft.

Read the end reactions and maximum moment

Use the numbers only to check elementary statics or communicate a preliminary load case to the designer.

Loads and member checks outside this model

Off-center loads, partial uniform loads, multiple point loads, cantilevers, continuity, self-weight, lateral-torsional behavior, load combinations, and connection eccentricity are excluded.

Questions specific to this calculation

What beam and load case does this calculator solve?

It assumes one simply supported span with a full-length uniform load and one point load at midspan. The reactions are symmetric, and the displayed maximum moment combines wL²/8 with PL/4.

Can the result be used to select a beam?

No. The tool does not check shear, deflection, material resistance, lateral stability, connections, bearing, load combinations, or code-required factors. A qualified designer must define loads and verify the member.