Lintel Load Calculator

Calculate the total load and bending moment on a lintel.

Created by Luis GonzalezLast updated: May 9, 2026

How to Use This Calculator

1
Enter Span (ft)
Input the clear span of the lintel or header in feet. This is the horizontal distance between supports.
2
Enter Tributary Width (ft)
Input the width of the wall area that the lintel is supporting, measured in feet. This is often half the distance to the next opening or support on each side.
3
Enter Load (psf)
Input the uniformly distributed load on the wall, in pounds per square foot (psf). This includes dead load (weight of wall, roof) and live load (occupants, snow).
4
Review Load and Moment Results
The calculator will display the total load, distributed load, maximum bending moment, and end reactions on the lintel.

Example Calculation

A builder needs to calculate the load on a 6-foot lintel spanning a window opening. The lintel supports a wall with a tributary width of 14 feet, subject to a combined load of 50 psf.

Span (ft)

Tributary Width (ft)

Load (psf)

Results

4200 lb

Tips

Distinguish Dead vs. Live Load

For structural accuracy, separately calculate dead load (permanent weight of materials like masonry, roof structure) and live load (variable weight like snow, occupants, furniture). Building codes often require these to be considered distinctly for safety.

Understand Tributary Width

The tributary width is the effective width of the load-bearing area that the lintel supports. Incorrectly estimating this can lead to significant under- or over-design. For interior walls, it might be half the distance to the next joist or beam.

Factor in Load Combinations

Structural design often requires considering various load combinations (e.g., dead + live, dead + snow + wind). The 'Load (psf)' input should represent the highest expected combined uniformly distributed load for conservative design.

Engineering Safe Structures: The Lintel Load Calculator

The Lintel Load Calculator is an essential engineering tool for architects, structural engineers, and contractors, providing crucial calculations for designing and verifying lintels (headers) over openings. It quickly determines the total load, distributed load, and maximum bending moment acting on a lintel, along with the end reactions on its supports. By inputting the span, tributary width, and load in pounds per square foot (psf), users can ensure that their structural elements are adequately sized and reinforced to safely carry the weight of the building above. Precise load calculations are paramount for compliance with current building codes, such as the International Building Code (IBC) 2024, and for guaranteeing long-term structural integrity.

Why Lintel Load Calculations Are Critical for Safety

Lintel load calculations are not merely an academic exercise; they are a fundamental requirement for ensuring the safety and stability of any building structure. A lintel's primary function is to bridge an opening, transferring the weight of the wall, floor, and roof above it to the adjacent vertical supports. If the lintel is undersized or under-designed for the actual loads it will bear, it can lead to excessive deflection, cracking in the masonry or drywall, and in severe cases, catastrophic structural failure. Proper calculation, therefore, prevents costly repairs, ensures occupant safety, and adheres to strict engineering standards.

The Engineering Behind Lintel Load and Moment

The Lintel Load Calculator applies fundamental principles of structural mechanics to determine the forces acting on a simply supported lintel under a uniformly distributed load.

Distributed Load (w): This is the load per lineal foot (plf) that the lintel must support. It's calculated by multiplying the tributary width by the area load.
```
Distributed Load (w) = Tributary Width (ft) × Load (psf)
```
Total Load (W): The overall weight supported by the lintel is the distributed load multiplied by the span.
```
Total Load (W) = Distributed Load (w) × Span (ft)
```
Maximum Bending Moment (M_max): For a uniformly loaded, simply supported beam, the maximum bending moment occurs at the center of the span.
```
Max Moment (M_max) = (w × Span²) / 8
```
End Reaction (R): Each support carries half of the total load.
```
End Reaction (R) = Total Load (W) / 2
```

These calculations provide the critical values needed to select an appropriate lintel material and cross-section.

💡 If you're also estimating the number of lintel blocks needed for your openings, our Lintel Block Calculator can help you quantify material requirements.

Analyzing a Window Header's Load: A Worked Example

Consider a structural engineer designing a header for a 6-foot wide window opening in a masonry wall. The wall section above the window has a tributary width of 14 feet, and the combined dead and live load (including wall, roof, and snow) is estimated at 50 pounds per square foot (psf).

Here’s how the Lintel Load Calculator determines the forces:

Span (ft): 6 ft
Tributary Width (ft): 14 ft
Load (psf): 50 psf

Calculations:

Distributed Load (w): 14 ft × 50 psf = 700 lb/ft.
Total Load (W): 700 lb/ft × 6 ft = 4200 lb.
Max Moment (M_max): (700 lb/ft × 6 ft²) / 8 = (700 × 36) / 8 = 25200 / 8 = 3150 lb-ft.
End Reaction (R): 4200 lb / 2 = 2100 lb (each).

The lintel must be designed to safely carry a total load of 4200 lbs, resist a maximum bending moment of 3150 lb-ft, and transfer 2100 lbs to each supporting jamb.

💡 For other construction material calculations, such as the weight of concrete components, our Sand Weight Calculator for Concrete can provide similar critical data.

Industry Benchmarks for Lintel Loads

Industry benchmarks for lintel loads are highly variable, depending on the type of construction (wood frame, masonry, steel), geographical location (snow load, wind load), and specific building codes (e.g., IBC, IRC). However, some general ranges can provide context:

Residential Wood Frame (Interior Opening): For a non-load-bearing partition wall opening (e.g., 3-foot door), the lintel might only need to support drywall and light framing, with distributed loads as low as 10-20 pounds per lineal foot (plf).
Residential Wood Frame (Exterior Load-Bearing): For an exterior wall supporting a roof and a second story (e.g., 6-foot window), distributed loads can range from 100-300 plf, with total loads potentially reaching 1,000-2,000 lbs, requiring engineered lumber or steel.
Masonry Walls: As demonstrated in the example (700 lb/ft), masonry walls generate significantly higher loads due to their inherent weight. Distributed loads for masonry lintels can easily exceed 500-1000 plf, necessitating reinforced concrete or steel lintels.
Commercial/Industrial: For large openings in commercial buildings, especially those supporting heavy equipment or multiple floors, distributed loads can climb into the thousands of plf, demanding robust steel beams or pre-stressed concrete members.

Always consult a licensed structural engineer and local building codes for precise load requirements, as these benchmarks are illustrative and not substitutes for professional design.

Frequently Asked Questions

What is a lintel in construction?

A lintel, also known as a header or beam, is a horizontal structural member that spans an opening in a wall, such as a door or window. Its primary function is to support the weight of the wall or structure above the opening, transferring those loads to the vertical supports (jambs) on either side. Lintels can be made from various materials, including wood, steel, concrete, or masonry.

Why is calculating lintel load important?

Calculating the load on a lintel is crucial for structural integrity and safety. An undersized lintel can deflect excessively, crack, or even fail, leading to damage or collapse of the wall above. Proper load calculation ensures that the lintel is adequately sized and reinforced to safely carry all anticipated dead and live loads, complying with building codes and engineering standards.

What is 'distributed load' on a lintel?

The 'distributed load' on a lintel refers to the weight that is spread uniformly along its length, typically measured in pounds per lineal foot (plf). This load is derived from the wall area (tributary width) and the weight per square foot (psf) that the lintel supports. It's a key value for engineers as it directly influences the bending moments and shear forces within the lintel.

What is 'maximum bending moment' on a lintel?

The 'maximum bending moment' is the point along the lintel's span where it experiences the greatest internal stress due to bending forces, usually at the center for a uniformly loaded, simply supported lintel. This value, measured in pound-feet (lb-ft), is critical for selecting the appropriate size and material of the lintel, as it dictates the required strength and stiffness to resist deflection and failure.