Beam Load Calculator
Calculate the maximum bending moment, shear force, bending stress, shear stress, and deflection of a simply supported or cantilever beam under a uniform distributed load, a point load, or both — with strength checks against allowable stresses and a serviceability check against common L/360, L/240, and L/180 deflection limits.
Input
Meters. For a cantilever, this is the length from the fixed support to the free end.
kN/m, spread across the full span. Leave blank for none.
kN, applied at mid-span (simply supported) or at the free end (cantilever). Leave blank for none.
Cross-section properties
mm⁴ — the section's second moment of area about the bending axis. Used for deflection and bending stress.
mm — from the neutral axis to the outer face (half the section depth for a symmetric section).
mm² — used for the shear stress estimate.
Material & stiffness
Sets the elastic modulus E. Pick Custom to enter your own value.
MPa. Leave blank to skip the bending strength check.
MPa. Leave blank to skip the shear strength check.
Output
| Metric | Value |
|---|---|
| No data yet | |
More ways to use this tool
REST API
curl -X POST https://api.iotools.cloud/v1/tool/beam-load-calculator \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"beamType": "simply-supported",
"span": "3",
"udl": "5",
"pointLoad": "10",
"momentOfInertia": "8360000",
"extremeFiberDistance": "150",
"crossSectionArea": "5000",
"shearShape": "average",
"material": "structural-steel",
"elasticModulus": "",
"allowableBendingStress": "150",
"allowableShearStress": "100",
"deflectionLimit": "360"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `beam-load-calculator` tool (Beam Load Calculator) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.
Embed widget
<iframe
src="https://iotools.cloud/embed/beam-load-calculator/"
width="100%" height="520" frameborder="0" scrolling="no" loading="lazy"
title="Beam Load Calculator — iotools.cloud"
sandbox="allow-scripts allow-forms allow-same-origin allow-downloads allow-popups allow-popups-to-escape-sandbox"
allow="clipboard-write"
style="width:100%;border:1px solid #e5e7eb;border-radius:12px;overflow:hidden"></iframe>
<script src="https://iotools.cloud/embed.js" async></script>Drop this into your own page — free, no key required, just a link back.
| Cost per API/MCP call | From 5 credits |
|---|---|
| Need more credits? | View pricing |
Also available with
Guides
Run a preliminary design check on a single-span beam in one pass: maximum bending moment, maximum shear force, the resulting bending and shear stresses, and the elastic deflection — for a simply supported or cantilever beam under a uniform distributed load, a point load, or both. Add an allowable bending or shear stress to get a pass/fail strength check, and pick a deflection limit to get a serviceability check, without switching between separate moment, stress, and deflection calculators.
How to use it
- Pick the beam type — simply supported (resisted at both ends) or cantilever (fixed at one end, free at the other).
- Enter the span (L), then a distributed load (w), a point load (P), or both — leave either blank to skip it.
- Enter the section's moment of inertia (I), distance to the extreme fiber (c), and cross-sectional area (A) — and pick the section shape that best matches yours, which sets the shear-stress distribution factor.
- Choose the material to fill in the elastic modulus E, or select Custom to enter your own.
- Optionally enter an allowable bending stress and/or allowable shear stress to get a pass/fail strength check, and pick a deflection limit (L/360, L/240, or L/180) for the serviceability check.
Results update as you type.
The formulas
For both loading cases, the distributed load's and the point load's individual peak moment and peak shear land at the same location — midspan for a simply supported beam, the fixed support for a cantilever — so the combined peak is just the sum of the two closed-form peaks:
- Simply supported: M = wL²/8 + PL/4, V = wL/2 + P/2
- Cantilever: M = wL²/2 + PL, V = wL + P
Bending stress follows the flexure formula, σ = M·c/I. Shear stress is estimated as τ = k·V/A, where k is 1.5 for a rectangular section, 4/3 for a circular one, and 1 for an average estimate or a wide-flange web taken alone. Deflection reuses the same simply-supported and cantilever formulas as the Beam Deflection Calculator, superposed the same way.
Reading the checks
The serviceability check divides the span by the computed deflection and compares it against whichever limit you picked — L/360 for live-load-sensitive floors, L/240 for a typical total-load limit, or L/180 for less critical members. The strength checks only appear once you enter an allowable stress, and compare the computed bending or shear stress directly against it — a straightforward PASS/FAIL, not a factored code check.
Limits
This is a preliminary check, not a final design tool. It assumes a prismatic (constant cross-section) beam, ignores shear deformation in the deflection calculation, and covers only the two loading cases above — not multiple point loads, partial-span distributed loads, or multi-span (continuous) beams. The shear stress estimate depends on the section shape you pick; for anything other than a simple rectangular or circular section, treat it as an approximation. Verify every result against your governing design code before relying on it.
Privacy
Everything runs in your browser — no dimensions or load data are sent anywhere.
Related tools
For just the support reactions, use the Beam Reaction Calculator. For deflection alone, without the stress checks, use the Beam Deflection Calculator.