Commercial Concrete Slab, Ready-Mix & Rebar Calculator
Converts slab dimensions into exact cubic yards for ready-mix truck dispatch, 80-lb/60-lb bagged concrete pallet loads, and #4 rebar grid stick counts with commercial spillage buffers.
1. Slab Dimensions & Thickness
2. Steel Reinforcement & Pour Spillage
Concrete Volume, Bag Yield & Pallet Conversion Chart
Authoritative industry reference data complying with ACI 318 Building Code Requirements for Structural Concrete / ACI 302 Concrete Slabs.
| Volume (Cubic Yards) | Cubic Feet | 80-lb Bags (0.60 cu ft) | 60-lb Bags (0.45 cu ft) | Full Pallets (80-lb) |
|---|---|---|---|---|
| 0.5 yd³ | 13.5 cu ft | 23 bags | 30 bags | 0 pallets + 23 loose |
| 1.0 yd³ | 27.0 cu ft | 45 bags | 60 bags | 1 pallet + 3 loose |
| 2.0 yd³ | 54.0 cu ft | 90 bags | 120 bags | 2 pallets + 6 loose |
| 3.0 yd³ (Ready-Mix min) | 81.0 cu ft | 135 bags | 180 bags | 3 pallets + 9 loose |
| 5.0 yd³ | 135.0 cu ft | 225 bags | 300 bags | 5 pallets + 15 loose |
| 10.0 yd³ (Full Truck) | 270.0 cu ft | 450 bags | 600 bags | 10 pallets + 30 loose |
Transparent Engineering & Takeoff Formulas
Mathematical logic, material density constants, and waste multipliers used in this calculator.
1. Cubic Feet of Concrete
Cubic_Ft = Length (ft) × Width (ft) × (Thickness_Inches ÷ 12)Geometric volume of slab excavation or formwork.
2. Ready-Mix Truck Cubic Yards
Cubic_Yards = round(((Cubic_Ft ÷ 27) × (1 + Waste_Pct / 100)), 2)Ready-mix batch plants charge by the cubic yard (27 cu ft) with minimum order thresholds.
3. 80-lb Pre-Mix Concrete Bags
Bags_80lb = ceil((Cubic_Ft × (1 + Waste_Pct / 100)) ÷ 0.60)One standard 80-lb bag of concrete yields exactly 0.60 cubic feet of mixed concrete.
4. Full Pallet Tally
Pallets = floor(Bags_80lb ÷ 42) + Remainder_Loose_BagsCommercial 80-lb concrete pallets are shrink-wrapped with exactly 42 bags (3,360 lbs).
5. Rebar Grid Linear Feet & 20-ft Sticks
Linear_Ft = ((Length ÷ Spacing + 1) × Width + (Width ÷ Spacing + 1) × Length) × 1.10Two-way rebar grid (12" or 18" OC) including 10% overlap splices and corner hooks.
Frequently Asked Commercial Takeoff Questions
Answering high-intent contractor questions on specifications, sizing, and code requirements.
How many 80-lb bags of concrete are in a cubic yard?
There are exactly 45 bags of 80-lb concrete in one cubic yard (27 cu ft ÷ 0.60 cu ft yield per bag = 45 bags). For 60-lb bags (yielding 0.45 cu ft), you need 60 bags per cubic yard.
When should I order a ready-mix truck instead of mixing bags?
As a rule of thumb, any pour requiring more than 1.5 to 2.0 cubic yards (over 70 to 90 eighty-pound bags) justifies ordering a ready-mix delivery truck. Hand-mixing 90 bags causes cold joints and requires significant manual crew labor.
What thickness should a commercial slab be?
Residential sidewalks and patio slabs are typically poured at 4 inches (3,000 PSI). Driveways and light commercial slabs are poured at 5 to 6 inches (4,000 PSI with #4 rebar on 12" OC chairs). Heavy equipment pads require 8+ inches.
How much spillage / waste buffer should be ordered for concrete?
Always add 5% waste for structured framed slabs on flat ground, and 10% for uneven dirt subgrade or sonotube deep hole excavations where sub-base depressions consume extra yardage.
How many bags of concrete fit on a pallet?
A standard pallet holds 42 bags of 80-lb concrete (weight: 3,360 lbs) or 56 bags of 60-lb concrete (weight: 3,360 lbs).
Complete Your Job Takeoff — Next Phases
Sequentially calculate adjacent phases and combine all items into your Master Project Takeoff Cart.