Beam Deflection Calculator | Supported & Cantilever

Calculate beam deflection, bending moment, and reaction forces for simply supported, cantilever, and fixed beams

Includes shear and moment diagrams and a...

When Should You Use This Calculator?

Finding max deflection and bending moment for common beam scenarios
Validating support/load combinations with explicit solver coverage messaging
Reviewing normalized shear, moment, and deflection plots on demand
Using the section property calculator to derive area moment of inertia before solving
Checking reaction forces and flexural rigidity for engineering decisions

Key Features:

All 4 beam types and 4 load types available directly from the dropdowns
Support/load solver coverage messaging for unsupported combinations
Deflection, bending moment, reaction forces, and flexural rigidity
Expandable normalized shear/moment/deflection plots and section inertia calculator
Copy results and export (JSON for guests; PDF/CSV when signed in)

Frequently Asked Questions

Why is beam deflection important?

Excessive deflection can crack finishes, jam doors, or be visually unsettling. Building codes limit deflection (e.g., L/360) to ensure serviceability and safety.

How does Moment of Inertia affect deflection?

Moment of Inertia (I) represents a beam geometry's resistance to bending. A higher "I" value (deeper beam) significantly reduces deflection. Doubling beam depth reduces deflection by a factor of 8.

Which beam support type should I choose?

Simply supported beams are supported at both ends and free to rotate. Cantilever beams are fixed at one end and free at the other (more deflection for the same load). Fixed-fixed beams are constrained at both ends (least deflection). Choose the type that matches your physical setup.

What is the difference between a point load and a distributed load?

A point load (concentrated force) acts at a single location. A uniformly distributed load (UDL) spreads evenly over the beam length, like the weight of flooring. A distributed load causes roughly half the maximum deflection of an equivalent point load at mid-span.

Can I export my Beam Deflection & Bending Moment Calculator calculations?

Yes. In guest mode you can export your calculations to JSON. Signing in adds PDF and CSV export. Click the export button to download your results — useful for record-keeping, sharing, or importing into other tools.

Does this calculator save my history?

Yes. Your calculation history is saved automatically. As a guest you can keep up to 50 calculations per workspace on your device. Sign in for free to keep up to 100 per workspace and access them from any device.

Is this calculator free to use?

Yes. The Beam Deflection & Bending Moment Calculator is free to use with no sign-up required. A free account adds more calculation history, multiple workspaces, and access to your saved data from any device.

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