Lintel Calculator

Calculate lintel size and concrete volume for door and window openings. Enter span, load type, and wall thickness.

πŸͺ¨ Lintel Calculator

Results

Min Lintel Depth5 in
Min Bearing (each end)18.00 in
Concrete per Lintel0.83 cu ft
Total Concrete3.3 cu ft
80 lb Bags6 bags

πŸ’‘ How to Calculate Lintels

A lintel is a horizontal beam spanning an opening (door, window) to carry the load above. Minimum lintel depth is typically span/8 for light loads, deeper for heavier loads. Bearing length on each end should be at least half the span or 4 inches, whichever is greater.

Concrete lintels are reinforced with rebar β€” typically 2 bars in the bottom for spans up to 4 feet, and 3–4 bars for wider spans. For pre-cast lintels, sizes are standardized. For cast-in-place, form the lintel in position and pour with at least 3,000 PSI concrete.

A 36-inch window opening with 8-inch wall: minimum lintel depth = 4.5 inches (use 5 inches). Concrete volume per lintel = 36 Γ— 8 Γ— 5 / 1728 = 0.83 cu ft. Four lintels = 3.3 cu ft β‰ˆ 6 bags of 80 lb mix.

Lintel Calculator FAQ

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