Lintel Size Calculator

Inputs

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Used for method notes only. Enter the actual section and allowable values for the selected member.
Clear width of the door, window or masonry opening.
ft
Support length at the left end. The effective span assumes reactions act near mid-bearing.
in
Support length at the right end. The smaller bearing is used for bearing pressure.
in
Height of wall area treated as loading the lintel.
ft
Wall dead/live surface load. In imperial this is psf.
psf
Additional uniform line load delivered by floor, roof, beam or framing above the opening.
lb/ft
Self-weight or extra uniform allowance for the lintel member.
lb/ft
Optional centered load from a post, beam or concentrated framing reaction.
lbf
Elastic section modulus about the bending axis of the lintel member.
in³
Area moment of inertia about the bending axis.
in⁴
Effective shear area for first-pass average shear stress. Use a conservative area for built-up or angle sections.
in²
Elastic modulus for deflection. Steel is about 29 Mpsi; many LVL products are about 1.8-2.2 Mpsi.
Mpsi
Allowable or design bending stress for the selected material and design basis.
ksi
Allowable or design shear stress for the selected material and section.
ksi
Width or thickness of the supported bearing area under the lintel reaction.
in
Allowable bearing pressure/stress for the support material. In imperial, 100 psi = 0.1 ksi.
ksi
For L/360, enter 360. This limit is compared against total service load deflection.

Results

Default result
Edit inputs
Governing utilization(U_max)
0.6857
Pass

Governing check: bearing pressure.

Also computed

Allowable uniform line load(w_allow)Pass933.3lb/ft

Minimum of bending, shear, deflection and bearing uniform-load capacities with the centered point load held fixed.

Required section modulus(S_req)0.8836in³

S_req = M / allowable bending stress.

Required moment of inertia(I_req)1.357in⁴

I_req from the entered L/n deflection limit.

Effective simple span(L_eff)4.5ft

Clear opening plus half of each bearing length.

Total uniform line load(w)640lb/ft

Wall line load plus floor/roof line load plus lintel self-weight.

Wall line load(w_wall)320lb/ft

Wall area load multiplied by tributary height.

Lintel sizing preview: Within entered limits, governing utilization 0.69Lintel sizing previewSimple-span opening screen from wall/floor line load, section S/I and bearing.effective simple spangoverning0.69Within entered limitsline load640 lb/ftBending0.59Deflection0.45Bearing0.69
Method notes 4 notes
  • Effective span is approximated as clear opening plus half of each bearing length, assuming reactions near the middle of the bearing zones.
  • Simple-span formulas: M = w*L^2/8 + P*L/4, V = w*L/2 + P/2 and delta = 5*w*L^4/(384*E*I) + P*L^3/(48*E*I).
  • Entered material basis: steel lintel values should come from the selected angle, channel or beam section and the governing steel design basis.
  • This is a preliminary service-load screen. It does not replace local code, manufacturer tables, reinforcement design, lateral-torsional buckling, web/local buckling, connection design, fire rating, masonry arching, load combinations or permit/engineer review.

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