How Much Concrete Do I Need for a Patio? (Complete Guide)

The Quick Answer

For a standard 4-inch thick patio, you need approximately 1.23 cubic yards of concrete per 100 square feet. A typical 10x10 patio needs about 1.23 cubic yards, a 12x12 patio needs about 1.78 cubic yards, and a 12x16 patio needs about 2.37 cubic yards.

Use our free concrete calculator above to get an exact number based on your specific dimensions. The calculator accounts for slab thickness, shape, and even estimates cost and bag counts.

How to Calculate Concrete for a Patio

The formula is simple: Length (ft) × Width (ft) × Thickness (ft) ÷ 27 = Cubic Yards. The division by 27 converts cubic feet to cubic yards, which is how concrete is sold.

For example, a 12x16 patio that is 4 inches thick: 12 × 16 × 0.333 ÷ 27 = 2.37 cubic yards. Always round up and add 5-10% extra for waste, spillage, and uneven ground.

If using bagged concrete instead of ready-mix, know that one 80-pound bag yields about 0.6 cubic feet of mixed concrete. For our 12x16 example, you would need approximately 107 bags --- which makes ready-mix delivery much more practical for anything over 1 cubic yard.

Common Patio Sizes and Concrete Needed

8×10 patio (80 sq ft): 0.99 cubic yards at 4" thick --- approximately 45 bags of 80-lb mix or $120-$160 for ready-mix delivery.

10×10 patio (100 sq ft): 1.23 cubic yards at 4" thick --- approximately 56 bags or $150-$200 for ready-mix.

10×12 patio (120 sq ft): 1.48 cubic yards at 4" thick --- approximately 67 bags or $180-$240 for ready-mix.

12×12 patio (144 sq ft): 1.78 cubic yards at 4" thick --- approximately 80 bags or $215-$285 for ready-mix.

12×16 patio (192 sq ft): 2.37 cubic yards at 4" thick --- approximately 107 bags or $285-$380 for ready-mix.

16×20 patio (320 sq ft): 3.95 cubic yards at 4" thick --- ready-mix delivery strongly recommended at $475-$630.

How Thick Should a Concrete Patio Be?

Standard residential patios should be 4 inches thick. This is the minimum recommended by most building codes and provides adequate strength for foot traffic, patio furniture, and light use.

If the patio will support heavy items like a hot tub, outdoor kitchen, or is used as a parking pad, increase thickness to 5-6 inches. Vehicle traffic requires a minimum of 6 inches with reinforcement.

The sub-base is equally important. Compact 4-6 inches of gravel before pouring to ensure proper drainage and prevent cracking from ground movement. In cold climates, extend the gravel base deeper to protect against frost heave.

Cost Breakdown for a Concrete Patio

Ready-mix concrete costs $120-$160 per cubic yard delivered. For a 12x12 patio (1.78 cu yd), the concrete alone costs approximately $215-$285.

Additional material costs include: gravel base ($25-$50), forms and stakes ($30-$80), rebar or wire mesh ($50-$100), and concrete sealer ($20-$40). Total materials for a DIY 12x12 patio run $340-$555.

Professional installation adds $4-$8 per square foot for labor. A professionally poured 12x12 patio typically costs $1,000-$2,200 total, depending on finishing (broom finish vs. stamped or colored concrete).

Tips for a Successful Patio Pour

Order 10% more concrete than calculated. Running short during a pour is extremely costly --- you cannot easily add concrete to a partially cured slab without creating a cold joint.

Check the weather forecast. Ideal pouring temperature is 50-80°F. Avoid pouring in direct hot sun (concrete cures too fast) or when rain is expected within 24 hours.

Have enough help on hand. Concrete waits for no one --- once the truck arrives, you typically have 60-90 minutes to place, screed, and finish the concrete before it becomes unworkable.

Cure the concrete properly. Keep the surface moist for at least 7 days by covering with plastic sheeting or spraying water daily. Proper curing develops 50% more strength than uncured concrete.

Reinforcement and Control Joints

Reinforcement keeps a slab together when the ground shifts and concrete shrinks. For most residential patios, welded wire mesh or a grid of half-inch rebar set on chairs in the middle of the slab is enough. Place reinforcement so it sits in the upper third of the slab, where it does the most good against surface cracking.

Control joints are intentional weak lines that tell the slab where to crack as it cures and shrinks, instead of letting random cracks wander across the surface. Cut or tool joints to about one quarter of the slab depth, and space them in feet no more than two to three times the slab thickness in inches. For a 4-inch patio, that means joints every 8 to 10 feet.

Fiber-reinforced concrete, where polypropylene fibers are mixed into the batch, is an increasingly popular add-on that reduces fine surface cracking. It complements rather than replaces mesh or rebar for slabs that will carry real load.

Frequently Asked Questions

How many bags of concrete do I need for a patio? An 80-pound bag yields about 0.6 cubic feet. A 10x10 patio at 4 inches is about 33 cubic feet, so roughly 56 bags. Beyond about a cubic yard, ready-mix delivery is cheaper and far less work.

Can I pour a patio in sections? Yes, but plan the joints deliberately so the sections look intentional. Pouring against a cured section creates a cold joint, which should fall on a planned control-joint line for the cleanest result.

How long before I can use a new concrete patio? You can usually walk on it after 24 to 48 hours, but wait 7 days before heavy furniture and 28 days for full design strength. Keep it damp during the first week for the strongest cure. Our concrete calculator gives exact yardage, bag counts, and cost for your dimensions.

Base Prep, Thickness, and Finishing Choices

A durable patio starts below the concrete. A four-inch slab is standard for foot traffic and patio furniture, sitting on a compacted gravel base four to six inches deep that provides drainage and a stable platform. Skimping on base prep is the most common cause of a patio that cracks and heaves within a few seasons, so the gravel, compaction, and a slight slope away from the house for drainage are not steps to cut.

Always order more concrete than your bare calculation suggests. Subgrade is never perfectly level, edges tend to over-dig, and some volume is lost to spillage, so adding 10 percent is the industry norm. Running short mid-pour is a serious problem because concrete cures continuously — a cold joint forms where fresh concrete meets a section that has already begun to set, creating a permanent weak line across your patio.

Finishing choices affect both cost and longevity. A broom finish is the most economical and provides slip resistance, while stamped or colored concrete adds a decorative surface at a premium. Regardless of finish, control joints cut or tooled into the slab every eight to ten feet give cracks a planned place to form instead of wandering randomly. Curing the slab properly — keeping it damp for several days — dramatically increases its final strength and is a free step too many DIYers skip.