Free Beam Calculator
Use this beam calculator online free to estimate maximum shear force, maximum bending moment, and maximum deflection for common beam cases.
What This Beam Calculator Online Free Does
This tool is a quick beam deflection calculator and bending moment calculator for two of the most common structural cases: simply supported beams and cantilever beams. It helps you perform first-pass checks during concept design, homework practice, and preliminary engineering discussions.
- Calculates max shear force (Vmax)
- Calculates max bending moment (Mmax)
- Calculates max deflection (δmax)
- Optionally calculates max bending stress (σmax) if c is entered
How to Use the Calculator
1) Choose support and load type
Pick whether your member is a simply supported beam or a cantilever beam. Then select either a point load or a uniformly distributed load (UDL).
2) Enter geometry and material data
Provide:
- L in meters
- E in GPa
- I in cm⁴
- Load in kN (point load) or kN/m (UDL)
3) Add optional stress input
If you know distance to extreme fiber c, enter it in mm. The calculator will use the flexure formula to estimate maximum bending stress.
4) Click “Calculate Beam”
Results are displayed instantly with peak values. This is ideal for quick checks before detailed modeling in software.
Beam Formulas Used
This online beam calculator free uses standard closed-form elastic beam equations:
Simply Supported Beam
- Point load at midspan: Vmax=P/2, Mmax=PL/4, δmax=PL³/(48EI)
- UDL over full span: Vmax=wL/2, Mmax=wL²/8, δmax=5wL⁴/(384EI)
Cantilever Beam
- Point load at free end: Vmax=P, Mmax=PL, δmax=PL³/(3EI)
- UDL over full length: Vmax=wL, Mmax=wL²/2, δmax=wL⁴/(8EI)
Bending Stress (optional)
If c is provided: σmax = Mmaxc / I.
Practical Notes for Real Projects
A free beam deflection calculator is great for screening concepts, but real structures usually require additional checks:
- Load combinations (dead, live, wind, seismic)
- Support settlement and fixity assumptions
- Shear deformation for short/deep beams
- Lateral-torsional buckling for slender steel members
- Serviceability limits (like L/360 or project-specific criteria)
- Code-based strength checks (AISC, Eurocode, ACI, etc.)
Worked Example (Quick)
Suppose a simply supported steel beam has L = 6 m, E = 200 GPa, I = 12000 cm⁴, and a central point load P = 18 kN. Enter those values and the calculator returns peak shear, moment, and deflection. If your section depth gives c = 140 mm, it also returns a quick bending stress estimate in MPa.
Why This Tool Is Useful
- Fast structural sanity checks
- Helpful for students learning shear force and bending moment behavior
- Useful for estimators and designers during concept phase
- No software install required
Frequently Asked Questions
Is this a shear force and bending moment diagram generator?
Not in graphical form. This version focuses on maximum values. It is intended as a quick beam analysis calculator.
What units are accepted?
Inputs are in m, GPa, cm⁴, kN, and kN/m. Outputs are shown in kN, kN·m, mm, and MPa.
Can I use it for continuous beams?
No. This page supports only single-span simply supported and cantilever beam cases with basic loading patterns.
Is this enough for final design?
No. Use it for preliminary checks only. Final structural design should include full code compliance and professional review.
Tip: Bookmark this page if you want a fast, reliable beam calculator online free for everyday engineering estimates.