Trapezoid Concrete Calculator
This trapezoid concrete calculator handles four-sided pours with two parallel edges — flared driveway aprons, tapered walks and wedge slabs. Enter both parallel sides, the distance between them, and the thickness.
Cómo usar esta calculadora
- Introduzca sus dimensiones — pies para longitudes, pulgadas para el espesor.
- Ajuste las opciones — porcentaje de desperdicio, tamaño de la bolsa y el precio local del hormigón.
- Lea sus resultados — el volumen, las bolsas, el peso y el costo se actualizan en vivo mientras escribe.
La fórmula
Trapezoid volume = ½ × (side A + side B) × height × thickness Ejemplo resuelto: An apron 12 ft at the street, 8 ft at the garage, 10 ft deep, 4 in thick: 0.5 × (12+8) × 10 × 0.333 = 33.3 ft³ ≈ 1.23 yd³.
The concrete calculator trapezoid formula averages the two parallel sides — a trapezoid is just a rectangle at the average width. Driveway aprons that flare to the street are the everyday example.
Measure the two parallel edges and the perpendicular distance between them (not a slanted side). Non-parallel side lengths don't enter the formula at all.
Sloped ramps are a different trapezoid — vertical rather than plan-view. For a ramp of constant width whose thickness tapers, use average thickness in the rectangle calculator: (thick end + thin end) ÷ 2.
Preguntas frecuentes
Preguntas comunes sobre la trapezoid concrete calculator.
How do I calculate a trapezoid slab?
Average the two parallel sides, then multiply by the distance between them and the thickness. ½(a+b) × h × t.
Which sides do I measure?
The two parallel edges (A and B) and the perpendicular height between them. The slanted connecting sides are not used.
How do I handle a sloping ramp?
For a ramp of constant width with tapering depth, use the rectangle calculator with the average of the two end thicknesses.
What waste factor for aprons?
5–10%. Flared aprons meet existing pavement, so edges are often ragged — round up.
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