Understanding Header and Beam Loads
Headers and beams carry weight from roofs, floors, walls, and openings. They do not work alone. Each member passes force into posts, studs, foundations, or other supports. A clear load path helps you estimate that force before choosing a size.
What This Calculator Does
This tool converts area loads into a line load. It uses tributary width, span, roof loads, floor loads, wall loads, and extra loads. It also accepts a centered point load. The result shows total load, reactions, bending moment, estimated deflection, bearing pressure, and simple pass checks.
Why Tributary Width Matters
Tributary width is the loaded width assigned to the header or beam. A beam supporting joists from both sides may receive half the joist span from each side. A header below a wall may receive floor, roof, and wall loads above it. Small width changes can produce large load changes.
Reading the Results
Pounds per lineal foot explains how much uniform weight acts along each foot. Total load shows the full weight on the span. Reaction tells what each end support carries when loads are balanced. Moment shows bending demand near midspan. Deflection estimates sag under service load.
Useful Design Notes
This page is for planning and education. Local codes, lumber grades, connection details, holes, notches, moisture, load duration, and lateral bracing can change the final design. Point loads away from midspan also change reactions and moment. Ask a licensed professional before construction.
Better Inputs Give Better Estimates
Use approved design loads from local code tables. Separate dead load from live or snow load when possible. Measure clear span, not rough opening width, when the beam bears beyond the opening. Use actual beam dimensions for strength and deflection checks. Save the CSV or PDF report for project notes, review, or later comparison with supplier tables.
Example Use
A builder may test two spans with the same roof load. The longer span usually raises bending and deflection faster than total weight. This is why beam depth often grows quickly. The calculator makes that pattern visible. It helps compare framing choices before drawings, permit review, or material ordering.
Record assumptions clearly. Shared notes reduce mistakes during estimating, bidding, inspection, and field layout work.