Projetos Externos

Calculadora de Concreto

Calcule o volume de concreto em metros cúbicos e o número de sacos pré-misturados para lajes e fundações.

⚡ Quick Dimensional Presets:

Medidas do Projeto

Digite as dimensões para calcular os materiais necessários

DRAFTING SPEC: CROSS-SECTION10 FT × 10 FT @ 4 IN

Insira as medidas acima para visualizar os resultados.

Exemplo Passo a Passo

Cenário: Pouring a 10 ft × 10 ft concrete patio slab that is 4 inches thick with a 10% safety buffer.

Convert 4" thickness to feet: 4 ÷ 12 = 0.333 ft.

Calculate Net Volume: 10 ft × 10 ft × 0.333 ft = 33.33 cu ft.

Add 10% Safety Buffer: 33.33 × 1.10 = 36.67 cu ft.

Convert to Cubic Yards: 36.67 ÷ 27 = 1.36 cubic yards.

Calculate 80 lb Bags: 36.67 cu ft ÷ 0.60 cu ft/bag = 61.1 -> 62 bags.

Result: You need 1.36 cubic yards of concrete (or 62 bags of 80lb pre-mix concrete).

Concrete Slab Volume Formula

Cubic Yards = (Length [ft] × Width [ft] × Thickness [in ÷ 12]) ÷ 27 × (1 + Waste %)

Multiply Length by Width by Thickness (converted to feet) to find volume in cubic feet. Divide cubic feet by 27 to obtain Cubic Yards. Add a 10% buffer to compensate for uneven ground and formwork deflection.

Variáveis da Fórmula

Cubic Feet — Length × Width × (Thickness in inches ÷ 12)

27 — Conversion constant (27 cubic feet = 1 cubic yard)

80 lb Bag Yield — 1 eighty-pound bag yields 0.60 cubic feet of mixed concrete

60 lb Bag Yield — 1 sixty-pound bag yields 0.45 cubic feet of mixed concrete

Premissas de Cálculo

One cubic yard equals 27 cubic feet (0.7645 m³).
An 80 lb bag yields 0.60 cu ft; a 60 lb bag yields 0.45 cu ft; a 40 lb bag yields 0.30 cu ft.
Ground subgrade is rarely perfectly level; a 10% overage buffer prevents running out during a pour.

Trade FAQ

Perguntas Frequentes

Dúvidas comuns sobre reformas e materiaisCalculadora de Concreto

When should I order a concrete truck instead of mixing bags?

As a general rule, if your project requires more than 1 cubic yard (approx 45–60 eighty-pound bags), ordering ready-mix delivery by truck is faster, produces higher structural strength, and saves strenuous manual labor.

How thick should a concrete slab be?

Sidewalks, walkways, and shed slabs should be 4 inches thick. Driveways supporting passenger vehicles should be 4 to 5 inches thick, and heavy RV pads or commercial driveways should be 6 inches thick with rebar reinforcement.

How many bags of concrete make 1 cubic yard?

It takes forty-five (45) 80 lb bags, sixty (60) 60 lb bags, or ninety (90) 40 lb bags to make exactly 1 cubic yard of solid concrete.

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