Load Bearing Beam Calculator

Estimate the load carried by a load-bearing beam using tributary width, floor load, roof load, wall load, beam span, and beam stiffness. Use this calculator for preliminary planning when replacing a load-bearing wall, sizing a header, checking a girder, or estimating support reactions.

Calculate Load Bearing Beam

Load-bearing beam line load = tributary width × area load + wall line load. Simple beam reaction = total load ÷ 2.
Your result will appear here.

How the load bearing beam calculator works

Floor load:
The calculator adds floor dead load and live load, then multiplies by tributary width to estimate floor line load.

Roof load:
The calculator adds roof dead load and live or snow load, then multiplies by tributary width to estimate roof line load.

Wall load:
The calculator adds wall line load directly to the beam load in pounds per linear foot.

Combined load:
The calculator combines floor load, roof load, wall load, and any additional point load into one load-bearing beam estimate.

Why use a load bearing beam calculator?

A load bearing beam calculator helps estimate how much weight a replacement beam or header may need to carry before discussing the project with a contractor, engineer, or building department.

It can help compare tributary area, total line load, beam load, support reactions, bending moment, shear, and basic deflection estimates.

What your result means

Your result shows estimated floor load, roof load, wall load, total line load, total beam load, support reactions, maximum shear, maximum bending moment, estimated deflection, allowable deflection, and span ratio. These are planning estimates only and do not replace structural design.

Load bearing beam formulas

Frequently asked questions

What is a load-bearing beam?

A load-bearing beam supports weight from floors, roofs, walls, posts, or other structural members and transfers that load to supports, posts, columns, or foundations.

What is tributary width?

Tributary width is the width of floor or roof area that contributes load to the beam. Multiplying tributary width by PSF load gives an estimated line load in PLF.

Can I remove a load-bearing wall using this calculator?

No. This calculator is only for rough planning. Removing or altering a load-bearing wall should be reviewed by a qualified contractor, structural engineer, or local building official.

Can this calculator size the final beam?

No. Final beam sizing depends on material, grade, section properties, load combinations, shear, bending, deflection, bearing, post loads, footing capacity, connections, code requirements, and professional review.