Concrete Column Calculator — ft, yd³, rebar
How to use this calculator
Select column shape (square, rectangular, or circular), enter dimensions in feet, inches, and fractions, set the height and number of columns. Results update instantly with volume, weight, and bag count.
Cost — pick ready-mix per yd³, 80-lb bags, or 60-lb bags.
Reinforcement — vertical bars #4–#8 with ties #3–#4, lap splices per ACI 318-19 §25.5, and min/max steel ratios (1%–8% Ag).
Labor — rate per column, per yd³, or flat price.
Saved Calculations
| Time | Shape | Size | Qty | Vol yd³ | Concrete $ | Rebar | Rebar $ | Labor | Total |
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How to Calculate Concrete for Columns
This concrete column calculator estimates volume in cubic yards, number of pre-mixed bags (60 lb and 80 lb), total weight, reinforcement (vertical bars and ties per ACI 318-19), and cost for square, rectangular, or circular columns. Enter dimensions in feet, inches, and fractions with 1/8″ precision. Set the column height (standard: 8–12 ft story height) and number of columns.
Reinforcement per ACI 318-19
Column longitudinal steel must be between 1% and 8% of gross cross-section area (Ag) per ACI 318-19 §10.6.1. Minimum 4 bars for tied columns. Tie spacing must not exceed: 16 longitudinal bar diameters, 48 tie bar diameters, or the least column dimension (§25.7.2). Lap splices are calculated at 40db for compression and 60db for tension/seismic zones.
Formulas
Square: V = side² × height. Rectangular: V = width × depth × height. Circular: V = π/4 × diameter² × height. Concrete density: 150 lb/ft³ (4,050 lb/yd³). Tie perimeter = 2×(width + depth) − 8×cover + 2×hook length.
FAQ
What is the minimum column size? ACI 318 does not set a minimum, but 10″×10″ is practical minimum for tied columns, 12″ for spiral columns. How many bags per column? A 12″×12″×10 ft column needs about 0.37 yd³ or 17 bags of 80-lb concrete.
