Beam Uniform Load
Calculator
Results
- Total load on the beam (kN)
- 40
- Reaction at each support (kN)
- 20
- Maximum bending moment (kN·m)
- 20
Construction results
| Total load on the beam (kN) | 40 |
| Reaction at each support (kN) | 20 |
| Maximum bending moment (kN·m) | 20 |
formula-map diagram
- Total load on the beam (kN)
- 40
- Reaction at each support (kN)
- 20
- Maximum bending moment (kN·m)
- 20
Formula breakdown
Formula
R = w × L ÷ 2; M_max = w × L² ÷ 8= 40
Note
Simplified model: results are quantity estimates only. They ignore openings, overlaps, cuts, site conditions and local building codes. Structural figures are not a substitute for a design by a qualified engineer.
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See all →Frequently asked questions
What is a uniformly distributed load, and how is it different from a point load?+
A uniformly distributed load (UDL) spreads evenly across the entire length of a beam (like the weight of a floor or roof deck), while a point load concentrates force at a single location (like a support column). This calculator models the UDL case, which uses different reaction and deflection formulas than a point-loaded beam.
How does the calculator find the reaction forces at each support?+
For a simply supported beam with a uniform load across its full length, each support reaction equals half the total load (w × L ÷ 2, where w is load per unit length and L is span), since a symmetric load on a symmetric beam splits evenly between both ends.
Why does the maximum bending moment occur at the beam's midpoint for a uniform load?+
With a symmetric load and symmetric supports, the bending moment builds from zero at each support and peaks where the upward reaction forces and downward distributed load balance out — for a simple span with uniform load, that point is exactly at mid-span, where the moment equals w × L² ÷ 8.
What units does the calculator expect for the load input?+
Distributed load should be entered as force per unit length (like pounds per foot or newtons per metre), not total force — if you know the total load and the beam's span, divide total load by span length first to get the correct per-unit-length input the formulas expect.
Does this calculator determine whether the beam size is actually adequate?+
It calculates the reactions and bending moment resulting from the load, which are necessary inputs for a full structural check, but confirming the beam is adequate requires comparing that moment (and the resulting stress) against the specific beam material and cross-section's allowable capacity — a separate engineering step beyond this calculator's scope.