Concrete Quantity Chart: Cubic Yards by Slab Size

Concrete Quantity Reference Chart

Use this pre-calculated table to quickly estimate how much concrete you need for rectangular slabs, patios, driveways, and sidewalks. Values are calculated using the standard formula: Cubic Yards = Length (ft) × Width (ft) × Depth (in) ÷ 12 ÷ 27. Bag counts assume 80 lb bags covering 0.6 cubic feet each. Add 10% extra for waste and uneven ground.

Slab Sizes at 4-Inch Depth (Standard for Patios & Sidewalks)

Slab Size (ft)	Cubic Yards	80 lb Bags	Common Use
4 × 4	0.20	9	Small pad, AC unit base
4 × 6	0.30	14	Small walkway section
4 × 8	0.40	18	Entry walkway
4 × 10	0.49	23	Short sidewalk
6 × 6	0.44	20	Trash can pad, small step
6 × 8	0.59	27	Garden shed pad
6 × 10	0.74	34	Small utility pad
8 × 8	0.79	36	Hot tub pad
8 × 10	0.99	45	Small patio
8 × 12	1.19	54	Shed foundation
10 × 10	1.23	56	Standard patio
10 × 12	1.48	67	Patio or walkway
10 × 14	1.73	78	Medium patio
10 × 16	1.98	89	Medium patio
12 × 12	1.78	80	Standard patio
12 × 14	2.07	94	Patio or carport pad
12 × 16	2.37	107	Large patio
12 × 20	2.96	134	Single-car driveway section
14 × 14	2.42	109	Workshop pad
14 × 16	2.77	125	Large patio
16 × 16	3.16	143	Large patio, small garage
16 × 20	3.95	178	Two-car parking pad
18 × 18	4.00	180	Large patio
20 × 20	4.94	223	Two-car driveway
20 × 24	5.93	267	Large driveway
24 × 24	7.11	320	Two-car garage floor
24 × 30	8.89	400	Large garage floor
30 × 30	11.11	500	Large workshop

Slab Sizes at 6-Inch Depth (Standard for Driveways & Garages)

Slab Size (ft)	Cubic Yards	80 lb Bags	Common Use
4 × 4	0.30	14	Heavy equipment pad
4 × 6	0.44	20	Reinforced walkway
4 × 8	0.59	27	Entry with vehicle traffic
4 × 10	0.74	34	Short driveway section
6 × 6	0.67	30	Heavy utility pad
6 × 8	0.89	40	Heavy shed foundation
6 × 10	1.11	50	Small driveway apron
8 × 8	1.19	54	Heavy equipment pad
8 × 10	1.48	67	Driveway section
8 × 12	1.78	80	Single-car apron
10 × 10	1.85	84	Driveway pad
10 × 12	2.22	100	Driveway section
10 × 14	2.59	117	Driveway extension
10 × 16	2.96	134	RV parking pad
12 × 12	2.67	120	Single-car driveway
12 × 14	3.11	140	Driveway section
12 × 16	3.56	160	Single-car garage floor
12 × 20	4.44	200	Single-car driveway
14 × 14	3.63	164	Workshop floor
14 × 16	4.15	187	Large workshop
16 × 16	4.74	214	Large single garage
16 × 20	5.93	267	Two-car parking
18 × 18	6.00	270	Large garage floor
20 × 20	7.41	334	Two-car garage floor
20 × 24	8.89	400	Oversized two-car garage
24 × 24	10.67	480	Three-car garage floor
24 × 30	13.33	600	Large shop floor
30 × 30	16.67	750	Commercial garage

Ordering Tips

• Under 1 cubic yard: Buy pre-mixed bags (80 lb bags are the most common). Mix in a wheelbarrow or rent a small mixer.
• 1 to 2 cubic yards: Consider renting a concrete mixer or ordering a short-load delivery from a ready-mix company.
• Over 2 cubic yards: Order a ready-mix truck. It is more cost-effective and ensures a consistent mix.
• Always add 10%: Order 10% more than calculated to account for waste, spillage, and uneven subgrade.
• Bag weight comparison: An 80 lb bag covers 0.6 cu ft. A 60 lb bag covers 0.45 cu ft. Use 60 lb bags if you prefer easier lifting.

Formula Used

All values in this chart are calculated using:

Cubic Yards = (Length in ft × Width in ft × Depth in inches ÷ 12) ÷ 27

80 lb Bags = Cubic Feet ÷ 0.6 (each 80 lb bag yields approximately 0.6 cubic feet of mixed concrete)

Source: Portland Cement Association standards for pre-mixed concrete bag yields.