Beam Load Calculator
Estimate support reactions, maximum bending moment, and deflection for a simply supported beam under a central point load or a uniformly distributed load. Calculates in your browser.
Show the math
For a simply supported beam the peak moment and deflection are:
point: M = PL/4, δ = PL³ ÷ 48EI
udl: M = WL/8, δ = 5WL³ ÷ 384EI
Deflection needs E and I; leave them blank to get reactions and moment only. Estimates for planning, confirm with an engineer. All math runs in your browser.
What this does
A beam load calculator estimates support reactions, maximum bending moment, and deflection for a simply supported beam under a central point load or a uniformly distributed load.
How to use it
- Choose point load or distributed load.
- Enter the load and span.
- Optionally enter E and I for deflection.
- Read the reactions and moment.
How it works
A simply supported beam is pinned at both ends. Deflection needs the elastic modulus E and second moment of area I. These are planning estimates — confirm structural work with a qualified engineer.
point: M = PL/4; distributed: M = WL/8
Understanding your result
These are planning estimates for a simple, pinned-end beam, not an engineering approval, and real structures have fixed ends, multiple loads, and safety factors this ignores. The maximum moment tells you where the beam is most stressed and the deflection whether it will feel springy, but anything load-bearing must be confirmed by a qualified engineer against the proper code.
Example
A 2 kN central load on a 4 m span gives a 2 kN·m maximum moment.
Sources & methodology
Last updated .
Frequently asked questions
Which beam case does this cover?
A simply supported beam (pinned both ends) with either a central point load (M = PL/4) or a uniformly distributed load (M = WL/8).
Do I need E and I for deflection?
Yes — deflection needs the elastic modulus E and second moment of area I. Leave them blank to get reactions and moment only.
Are these results safe to build from?
No — they are planning estimates. Always confirm structural work with a qualified engineer. Calculations run in your browser.
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