Load-Bearing Wall Calculator

About the Load-Bearing Wall Calculator

Load-bearing walls carry weight from the structure above and transfer it to the foundation below. Accurately calculating the load on a bearing wall is essential for sizing the wall studs, headers, and the foundation footing beneath it. The load comes from three main sources: the dead load (weight of materials), the live load (occupancy and use), and sometimes snow or wind loads.

This calculator computes the total load per linear foot on a bearing wall by summing the tributary loads from each supported level. You enter the tributary width (the distance of floor or roof that the wall supports) and the design loads for each level, and the calculator sums them into a total wall load.

Knowing the wall load is the first step in determining whether standard 2×4 studs at 16″ OC are adequate, or whether 2×6 studs, double top plates, or additional engineering are needed.

When This Page Helps

Understanding the load on a bearing wall drives decisions about stud size, header design, and foundation footings. This calculator simplifies the tributary load calculation so you can quickly evaluate different framing scenarios.

How to Use the Inputs

1. Enter the tributary width of the roof/ceiling supported by this wall.
2. Enter the dead and live loads for the roof (psf).
3. Enter the tributary width of the floor supported by this wall.
4. Enter the dead and live loads for the floor (psf).
5. Add levels as needed (second floor, attic, storage).
6. Read the total load per linear foot on the wall.

Example Calculation

Tips & Best Practices

• Interior bearing walls typically support half the floor span on each side—the tributary width is half the span left plus half the span right.
• Exterior walls support half the floor span on one side plus the roof overhang.
• Don't forget wall self-weight: a 2×4 stud wall with drywall both sides weighs about 7–8 plf.
• Multi-story loads are cumulative—a first-floor bearing wall carries the roof, second floor, and first floor loads.
• Use this load calculation to size the footing: footing width = load per foot / soil bearing capacity.
• When in doubt about which walls are bearing, consult the structural plans or an engineer.

Multi-Story Load Accumulation

For a first-floor bearing wall in a two-story home, the load includes: roof dead and live/snow loads, second-floor dead and live loads, first-floor dead load, and wall self-weights for both stories. Each level adds its tributary contribution. The first-floor wall and its footing must support the entire cumulative load.

Header Sizing for Openings

When a bearing wall has window or door openings, the load over the opening must be carried by a header beam. The header supports the wall load for its span and transfers it through jack studs to the foundation. Header sizing depends on both the span and the total wall load.

Foundation Considerations

The footing beneath a bearing wall must be wide enough to spread the wall load over the soil without exceeding the soil's bearing capacity (typically 1,500–4,000 psf for common soil types). Footing width = wall load (plf) / soil bearing capacity (psf).

Frequently Asked Questions

• How do I know which walls are load-bearing?

  Bearing walls typically run perpendicular to floor joists and support the ends or midspan of joists or trusses. They stack from roof to foundation. Walls parallel to joists are usually non-bearing unless they carry a beam above.

• What is tributary width?

  Tributary width is the distance of floor or roof area that depends on the wall for support. For an interior wall with equal joist spans on both sides, it's half the span on each side combined.

• What dead load do I use for a floor?

  Typical residential floor dead load is 10–15 psf, including joists, subfloor, and finish flooring. If there's tile flooring or heavy partitions above, add 5–15 psf more.

• What live load for residential floors?

  The IRC specifies 40 psf for habitable rooms, 30 psf for sleeping rooms (where allowed), and 10 psf for uninhabitable attics. Balconies and decks may be 40–60 psf depending on the jurisdiction.

• Can I remove a load-bearing wall?

  Yes, but you must install a beam (header) to replace the wall's structural function. The beam must be sized by an engineer to carry the same total load. Temporary shoring is required during construction.

• How does snow load affect a bearing wall?

  In snow regions, the ground snow load is converted to a roof snow load using factors for exposure and slope. This is added as a live load component on the roof. In heavy snow areas (50+ psf ground snow), this can be the dominant load on the wall.