Calculadora de Concreto para Agujeros de Poste — ft, bags, cost
Como usar esta calculadora
Seleccione el tamano de poste, diametro del agujero, profundidad del agujero y numero de postes. La calculadora resta el volumen del poste del volumen del agujero para determinar el concreto exacto necesario. Elija su tamano de bolsa preferido (40, 60 u 80 lb) para conteos precisos de bolsas.
Tamano de poste — los tamanos nominales usan dimensiones reales de madera (4×4 = 3.5"×3.5", 6×6 = 5.5"×5.5").
Diametro del agujero — debe ser minimo 3× el ancho del poste segun IRC.
Waste — add 10% por derrame y agujeros irregulares.
Calculos guardados
| Hora | Posts | Hole | Bags/Hole | Total de bolsas | Cost |
|---|
How to Calculate Concrete for Post Holes
This calculator determines the exact amount of concrete needed for fence posts, deck posts, mailbox posts, or any post set in concrete. It calculates the cylindrical hole volume, subtracts the square or round post volume, and converts to bags of premixed concrete.
Formulas Used
Hole volume: V = π × (diameter/2)² × depth
Square post volume: V = side² × depth
Round post volume: V = π × (diameter/2)² × depth
Concrete needed: hole volume − post volume + waste
Bag Yields
40 lb bag ≈ 0.30 ft³, 60 lb bag ≈ 0.45 ft³, 80 lb bag ≈ 0.60 ft³. These are approximate yields for standard premixed concrete (e.g., Quikrete, Sakrete).
Preguntas frecuentes
How deep should a post hole be? General rule: 1/3 of total post length underground, minimum 24" for fence posts, 42" below frost line for structural posts per IRC R403.1.
How wide should the hole be? IRC recommends 3× the post width. For a 4×4 post (3.5" actual), use a 10–12" diameter hole.
