Estimate deck beam load, beam span, tributary width, joist span carried, support reactions, maximum bending moment, bending stress, shear stress, deflection, and simplified maximum span. Use this deck beam calculator for deck beams, porch beams, drop beams, flush beams, post-supported beams, and preliminary structural planning.
Tributary width:
The calculator estimates how much deck width the beam carries from joist span or a custom tributary width.
Beam line load:
The calculator converts deck PSF load into PLF load on the beam, then adds beam self weight.
Beam section:
The calculator uses number of plies, ply width, and beam depth to estimate section modulus and moment of inertia.
Strength and deflection:
The calculator estimates bending, shear, reactions, deflection, span ratio, and simplified maximum span.
A deck beam calculator helps estimate whether a beam size, number of plies, post spacing, and deck load may be reasonable.
It can help compare beam line load, tributary width, support reactions, bending, shear, deflection, and approximate maximum beam span.
Your result shows estimated tributary width, deck load, beam line load, total beam load, post reactions, maximum moment, bending stress, shear stress, deflection, allowable deflection, span ratio, and estimated maximum span. These are planning estimates only.
A deck beam is a horizontal structural member that supports deck joists and transfers load to posts, footings, walls, or other supports.
Multiply the deck load in PSF by the tributary width carried by the beam, then add beam self weight and any point loads.
Tributary width is the width of deck area that sends load to the beam. A beam at the end of joists often carries about half the joist span, while some beams may carry a full joist span.
No. Final deck beam sizing should use approved span tables, local building code, lumber species and grade, beam connection details, post layout, footing size, lateral bracing, and professional review when needed.