Beam Stress & Deflection Calculator
Build a beam with supports and loads, then read off reactions, shear, bending moment, deflection and bending stress.

Cross-section

Second moment of area I = 6.67e+7 mm⁴ · Area = 20,000 mm²

Material / modulus

Supports

m
m

Point loads

m
kN

Distributed loads

No distributed loads.

Applied moments

No applied moments.

Results
Reactions and maximum response.

Support reactions

pin @ 0 m5 kN
roller @ 5 m5 kN
Max shear5 kN
Max bending moment12.5 kN·m
Max deflection1.905 mm
Max bending stress18.75 MPa
Safety factor (yield)19.73
Beam diagram
Shear, moment, stress and deflection are aligned beneath the loaded beam.
10 kN5 mLoading & deflected shape-5.00 kNShear force(kN)12.50 kN·mBending moment(kN·m)18.75 MPaBending stress(MPa)1.91 mmDeflection(mm)
About beam analysis

This tool solves Euler–Bernoulli beam bending using the direct-stiffness finite element method, so it handles cantilevers, simply-supported, overhanging, continuous multi-span and statically indeterminate beams. Sign convention: downward loads are positive, bending moment is sagging-positive, and deflection is reported downward.

Supports

Pinned and roller supports restrain vertical movement; a fixed support also restrains rotation and develops a reaction moment.

Section

Pick a standard profile to compute I and the extreme-fibre distance automatically, or enter the second moment of area directly from a datasheet.

Bending stress

Bending stress σ = M·y/I is evaluated along the span and compared against the material's yield strength for a safety factor.

Frequently Asked Questions

Worked example: Simply-supported 5 m beam with a central 10 kN point load

  1. Reactions: each support carries P/2 = 5 kN
  2. Max bending moment at mid-span M = PL/4 = 10 × 5 / 4 = 12.5 kN·m
  3. Max deflection δ = PL³/(48EI)

M_max = 12.5 kN·m at mid-span, with peak shear of 5 kN at the supports

What beam types can this calculator analyse?

It uses the finite element (direct stiffness) method, so it handles cantilevers, simply-supported, overhanging, propped and continuous multi-span beams, including statically indeterminate cases. Add any combination of pinned, roller and fixed supports.

Do I have to design the cross-section?

No. You can pick a standard profile (rectangle, circle, I-beam, hollow rectangle or tube) to compute the second moment of area automatically, or simply type in the second moment of area I from a datasheet and skip the geometry.

What sign conventions are used?

Downward loads and clockwise applied moments are positive, the bending moment is sagging-positive, positive shear is the net upward force on the segment to the left of a cut, and deflection is reported as positive downward.

How is the bending stress calculated?

Bending stress is σ = M·y/I, evaluated along the span using the local bending moment M and the distance y from the neutral axis to the extreme fibre. The peak stress is compared with the material's yield strength to give a safety factor.

What is free and what needs Pro?

Single-span beams (two supports) with point loads and uniform distributed loads, plus on-screen shear, moment and deflection diagrams, are free. Multi-span beams, applied moments, linearly varying loads, bending-stress utilisation, saving and branded PDF export are Pro features.