Lintel Calculator
Calculate lintel size and concrete volume for door and window openings. Enter span, load type, and wall thickness.
๐ชจ 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
๐ก 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 โ typically 2 bars in the bottom for spans up to 4 feet, and 3โ4 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 ร 8 ร 5 / 1728 = 0.83 cu ft. Four lintels = 3.3 cu ft โ 6 bags of 80 lb mix.