How Many Bags of Concrete for a 10x10 Slab? (Exact Yield Chart)
Poured concrete slabs for sheds, patios, and hot tubs require exact bag volume math. Here is the worked formula, bag yield table, and jobsite mixing advice.
1. The Core Volume Formula for Concrete Slabs
Calculating premix concrete bag requirements begins with determining total cubic feet. The formula converts slab length, width, and thickness into volume:
Concrete Volume Equation
Volume (Cu Ft) = Length (ft) x Width (ft) x [Thickness (in) / 12]
Volume (Cu Yds) = Volume (Cu Ft) / 27
2. Worked Math: 10x10 Slab at 4 Inches Thick
Let us calculate a standard 10ft x 10ft patio or shed foundation slab poured at 4 inches thickness (0.333 feet).
Step 1: Calculate Volume in Cubic Feet = 10 x 10 x (4 / 12) = 33.33 Cu Ft
Step 2: Add 10% Waste & Ground Variance = 33.33 x 1.10 = 36.66 Cu Ft
Step 3: Convert to 80lb Bags (Yield = 0.60 cu ft/bag) = 36.66 / 0.60 = 61 Bags
RECOMMENDED PURCHASE: 61 Bags of 80lb Concrete Premix
3. 10x10 Slab Bag Requirement Chart by Depth
| Slab Depth | Cubic Yards | 80lb Bags (0.60 cu ft) | 60lb Bags (0.45 cu ft) | 40lb Bags (0.30 cu ft) |
|---|---|---|---|---|
| 3 Inches (Pathways) | 0.93 Cu Yds | 42 Bags | 56 Bags | 84 Bags |
| 4 Inches (Standard Patio) | 1.23 Cu Yds | 56 Bags | 74 Bags | 111 Bags |
| 6 Inches (Driveway/Hot Tub) | 1.85 Cu Yds | 84 Bags | 111 Bags | 167 Bags |
Calculate Your Exact Concrete Bag Order
Enter custom slab dimensions, footings, or post holes to compute exact bags and cubic yards.
Launch Concrete CalculatorFrequently Asked Questions
How many 80lb bags of concrete are needed for a 10x10 slab at 4 inches thick?
A 10x10 slab at 4 inches depth requires 1.23 cubic yards of concrete (33.3 cubic feet). Since one 80lb bag yields 0.60 cubic feet, you need exactly 56 bags of 80lb concrete premix.
Is it cheaper to order a ready-mix concrete truck or mix bags for a 10x10 slab?
For a 10x10 slab requiring 1.23 cubic yards, mixing 56 bags of 80lb concrete costs roughly $330. Ordering a ready-mix truck costs $250 to $350 plus short-load delivery fees ($150 to $200). If you have 2 people, mixing bags or renting a portable drum mixer is usually more cost-effective.