Concrete Patio Calculator

Enter your patio's length, width, and thickness to instantly calculate concrete volume in cubic yards, number of bags needed, and total cost estimate.

Free to use No sign-up required Formulas verified against ACI 318 Imperial & metric supported

✓ Bag count (60 lb & 80 lb) ✓ Cost estimator included ✓ Works on any device ✓ Last verified May 2026

Reviewed by the AllConcreteCalculator.com editorial team — formulas cross-checked against ACI 318 standards, May 2026.

Enter Your Patio Dimensions

Patio Length

Measure the longest edge of the patio area. Please enter a valid length greater than 0.

Patio Width

The shorter dimension of the patio. Please enter a valid width greater than 0.

Slab Thickness

Standard patio: 4 inches. Attached to house or heavy furniture: 5–6 inches.

Please enter a valid thickness greater than 0.

Waste / Overage Factor (%)

Add 10% for standard rectangular patios. Increase to 15% for L-shapes or curves.

Price per Cubic Yard (optional)

Leave blank to skip cost estimate. US average: $100–$150/yd³ for ready-mix.

Results appear instantly. No sign-up required.

Your Concrete Estimate

Concrete Volume (with waste)

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Cubic Yards (yd³)

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Cubic Feet (ft³)

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Cubic Meters (m³)

Bags Required (includes waste)

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40 lb bags

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60 lb bags

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80 lb bags

— Area (sq ft)

— Area (m²)

— Thickness

— Waste Factor

Estimated Material Cost

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Concrete material cost only. Add labor ($3–$6/ft²), delivery ($100–$300), forming, and finishing for a full project budget. Use our Full Project Estimator for a complete breakdown.

Step 1: Convert all dimensions to feet
Step 2: Volume (ft³) = Length (ft) × Width (ft) × Thickness (ft)
Step 3: Cubic Yards = ft³ ÷ 27
Step 4: Final Volume = Volume × (1 + waste% ÷ 100)
Step 5: Bags = CEIL(Final ft³ ÷ bag yield) — never round down

Bag yields: 40 lb = 0.30 ft³ | 60 lb = 0.45 ft³ | 80 lb = 0.60 ft³

How to Use This Concrete Patio Calculator

Measure your patio footprint. Use a tape measure to get the outside length and width of your planned patio pour area — not the surrounding landscape or border edging. For L-shaped or irregular patios, split the area into separate rectangles, calculate each one, and add the results together. Record measurements in whichever unit you're most comfortable with.
Set your thickness and select units. Standard residential patios are poured at 4 inches. If your patio is attached to the house foundation, adjacent to a step, or will hold heavy outdoor furniture and a hot tub, use 5–6 inches. Use the quick-select buttons to fill in the most common patio thicknesses without typing. Make sure each dimension field shows the correct unit.
Adjust the waste factor. The default 10% waste is appropriate for a clean rectangular pour on a well-prepared, level subgrade. Increase to 15% for curved edges, irregular shapes, or anytime the subgrade is noticeably unlevel. Never drop below 5% — running short mid-pour forces a cold joint that will crack within a year.
Use the results to order materials. Give the cubic yards figure to your ready-mix supplier when ordering by truck. Use the bag counts if you're buying bagged concrete at a hardware store. For patios over 1 cubic yard, ready-mix delivery is almost always faster, cheaper per yard, and produces a more consistent pour than mixing bags by hand.

⚠ Pro Tip: The biggest mistake on concrete patio projects is skipping the gravel base. Pouring directly onto soil — even compacted soil — leads to uneven settling and cracking within a few freeze-thaw cycles. Excavate 6–8 inches, lay 4 inches of compacted gravel (crushed stone or road base), then pour your 4-inch slab on top. The gravel provides drainage and a stable, uniform bearing surface that concrete alone cannot create.

Concrete Patio Volume Formula

The calculation follows the same standard volumetric formula used for all flatwork, aligned with ACI 318 guidelines. For a patio, length and width are interchangeable — the formula produces identical results regardless of which dimension you call "length" or "width." Here's the process step by step:

Step	Formula	Example (16 × 12 ft, 4 in)
1. Convert thickness to feet	inches ÷ 12	4 ÷ 12 = 0.333 ft
2. Volume in cubic feet	L × W × T	16 × 12 × 0.333 = 64.00 ft³
3. Convert to cubic yards	ft³ ÷ 27	64.00 ÷ 27 = 2.370 yd³
4. Add waste factor (10%)	Volume × 1.10	2.370 × 1.10 = 2.607 yd³

Common Patio Size Reference Table

Concrete volumes and bag counts — no waste factor applied. Add 10% for real-world ordering.
Patio Size	Thickness	Cubic Yards	60 lb Bags	80 lb Bags
10 × 10 ft	4 in	1.23 yd³	74 bags	56 bags
12 × 12 ft	4 in	1.78 yd³	107 bags	80 bags
16 × 12 ft	4 in	2.37 yd³	143 bags	107 bags
20 × 12 ft	4 in	2.96 yd³	178 bags	134 bags
20 × 16 ft	4 in	3.95 yd³	237 bags	178 bags
24 × 16 ft	4 in	4.74 yd³	285 bags	214 bags
16 × 12 ft	5 in	2.96 yd³	178 bags	134 bags
20 × 16 ft	6 in	5.93 yd³	356 bags	267 bags
30 × 20 ft	4 in	7.41 yd³	445 bags	334 bags

Bag counts assume no waste factor. Add 10% for real-world ordering. For jobs over 1 cubic yard, ready-mix delivery is more economical.

What Thickness Does My Concrete Patio Need?

Patio thickness is the most common place homeowners and contractors underestimate. Too thin and the slab cracks under foot traffic, furniture loads, and freeze-thaw cycles within a few years. The table below covers real-world residential and light commercial patio applications.

Recommended concrete patio thickness by application and load type.
Patio Type / Use	Recommended Thickness	PSI Strength	Notes
Standard residential patio	4 inches	3,000 PSI	Wire mesh or rebar recommended
Patio with heavy outdoor furniture	4–5 inches	3,000 PSI	Thicker edges at 6 in if bordering a step
Patio attached to house foundation	5–6 inches	3,500 PSI	Match footing depth; control joints critical
Hot tub / spa pad	6 inches	3,500 PSI	Thicken to 8 in under legs; rebar required
Covered patio (pergola / roof load)	6 inches	3,500 PSI	Engineer review recommended for post loads
Commercial or high-traffic patio	6–8 inches	4,000 PSI	Air entrainment in freeze-thaw climates
Rooftop / elevated patio	3.5–4 inches	4,000 PSI	Structural deck must be engineered first

Going from 4 inches to 5 inches only adds 25% more concrete but dramatically improves slab longevity under point loads like furniture legs and post bases. On a 16 × 12 ft patio the difference is less than 0.6 cubic yards — roughly $75–$90 in ready-mix. It's almost always worth it.

Common Mistakes When Estimating Concrete for a Patio

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Skipping the compacted gravel base. Concrete does not bridge voids — it follows the subgrade beneath it. Pouring directly on soft, organic, or uncompacted soil guarantees settling and cracking within a few seasons. Excavate to stable ground, compact, and add at least 4 inches of crushed gravel before you form or pour anything. This step cannot be retrofitted after the fact.
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Forgetting the slope for drainage. A flat concrete patio will pond water, which accelerates surface deterioration and in cold climates creates ice hazards. The finished surface must slope away from the house at a minimum of 1/8 inch per foot (about 1%). This slope means the actual concrete depth at the high side is slightly thicker than at the low side — factor that into your thickness when ordering.
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Not cutting control joints deep enough or soon enough. Concrete shrinks as it cures and will crack — control joints direct where those cracks go. Joints should be cut to at least 1/4 of the slab thickness (1 inch for a 4-inch patio) and spaced no more than 10–12 feet apart in each direction. Cutting too late (more than 6–12 hours after pour) or too shallow means cracks wander wherever they want.
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Adding excess water to the mix on-site. Slicking up a stiff mix with extra water makes it easier to work, but every extra pound of water above the design water-cement ratio weakens the finished slab and increases shrinkage cracking. If the mix is too stiff to work, ask your ready-mix supplier to adjust the mix design — not the water at the chute.
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Finishing the surface before bleed water evaporates. Bleed water is the water that rises to the surface of fresh concrete as it consolidates. Finishing — troweling or brooming — before this water is fully gone traps water under the surface skin, creating a weak layer that will dust, scale, or delaminate within a year. Wait until the surface sheen disappears before any final finishing work.

Frequently Asked Questions

A 12 × 12 ft patio at 4 inches thick requires 1.78 cubic yards of concrete before adding a waste factor. With the standard 10% waste, you would order 1.96 cubic yards — round up to 2.0 yd³ when talking to your ready-mix supplier. If using bagged concrete, that works out to approximately 89 bags of 80 lb concrete (0.60 ft³ yield each) or 119 bags of 60 lb (0.45 ft³ yield each), including waste. Use the calculator above for the exact figures for any size.
The standard thickness for a residential concrete patio is 4 inches, which is adequate for foot traffic and standard outdoor furniture. If your patio will support a hot tub, planters heavier than a few hundred pounds, a pergola with post loads, or is attached to the house foundation, step up to 5–6 inches. In freeze-thaw climates, specify 3,500 PSI concrete with air entrainment (5–7% air) even at 4 inches — the air voids prevent surface scaling during winter. Going thicker costs surprisingly little: a 16 × 12 ft patio at 5 inches vs. 4 inches only uses about 0.6 more cubic yards of concrete.
A professionally installed concrete patio in the USA typically costs $6–$12 per square foot for a plain broom-finished slab, including concrete materials, labor, forming, gravel base, and basic finishing. Stamped or decorative concrete adds $8–$18 per square foot on top of the base cost. Exposed aggregate finishes fall in the $6–$10 per square foot premium range. Geographic location is the biggest cost variable — labor rates in coastal markets can be double those in rural Midwest areas. Material cost alone (concrete only, no labor) for a typical 4-inch patio runs $2–$3 per square foot at ready-mix prices.
For a standard 4-inch residential patio on a well-prepared gravel base, welded wire mesh (6×6 W1.4×W1.4 or "6×6 10/10") is the minimum most contractors recommend. It won't prevent cracking but it holds cracks tightly together if they develop, preventing them from opening wide and allowing water infiltration. Rebar (#3 or #4 on 18-inch spacing) is the better choice for patios supporting concentrated point loads like pergola posts, hot tubs, or anything attached to the house. Fiber reinforcement is also effective and easier to work with for small DIY pours — synthetic or steel macro-fibers at 1.5–3 lb per cubic yard significantly improve crack resistance compared to unreinforced concrete.
Yes, for patios up to about 1–1.5 cubic yards (roughly a 10 × 12 ft slab at 4 inches), a confident DIYer with a rented mixer can handle it successfully. Beyond that, the logistics of mixing, placing, screeding, and finishing concrete before it begins to set becomes very challenging for a single person or small crew. For anything over 1 cubic yard, ordering ready-mix is strongly recommended — the truck does all the mixing, the pour is continuous (no cold joints), and the concrete quality is consistent. If you order ready-mix, have at least two helpers on site: one running the chute and one screeding while you bull-float.
Foot traffic: 24–48 hours. Light furniture: 3–5 days. Heavy furniture, grills, and planters: 7 days minimum. Hot tubs and concentrated loads: 28 days for full design strength. Concrete reaches about 70% of its design strength at 7 days and 99% at 28 days. Do not let vehicles or heavy equipment on a residential patio slab — it is not designed for wheel loads. Keep the slab moist or covered with plastic sheeting for the first 7 days to allow proper curing (hydration); premature drying significantly reduces final strength.
A 10 × 10 ft patio at 4 inches thick requires 1.23 cubic yards (33.33 cubic feet) of concrete before waste. With 10% waste, that is 36.7 cubic feet total. You would need 62 bags of 80 lb concrete (0.60 ft³ yield per bag) or 82 bags of 60 lb concrete (0.45 ft³ yield per bag). At 80 lb bags, that's approximately 2.5 tons of material to transport and mix — most DIYers rent a portable mixer for pours this size. At 1.23 cubic yards, a ready-mix short-load delivery is also an option, though minimum load fees typically apply for orders under 3–4 yards.
The ideal temperature range for placing concrete is 50–85°F (10–29°C). Below 40°F (4°C), hydration slows dramatically and fresh concrete can freeze before gaining adequate strength — use heated enclosures or insulated blankets and add accelerating admixtures. Above 90°F (32°C), concrete sets much faster, reducing your working time and increasing the risk of plastic shrinkage cracking — use chilled water, shade the forms, and pour early morning. The absolute worst time to pour a patio is on a hot, sunny, windy day: moisture evaporates faster than the concrete can bleed, and the surface will crack before you can finish it.
Requirements vary widely by municipality. In most US jurisdictions, a freestanding concrete patio not attached to the house structure does not require a permit if it is below a certain size threshold — often 200–400 sq ft depending on the local code. However, patios attached to the house, located in flood zones, covering a certain percentage of lot area, or within setback distances from property lines may require permits and inspections. Always verify with your local building department before breaking ground. Permit violations can result in mandatory removal and fines, regardless of whether the work is done correctly.
Break the L-shape into two overlapping or non-overlapping rectangles, calculate each rectangle separately using this calculator, and add the results. For example, an L-shaped patio that is 20 × 10 ft along one section and 10 × 8 ft along the perpendicular arm: calculate 20 × 10 ft and 10 × 8 ft separately (making sure not to double-count the corner), then add the cubic yards. Add your waste factor only once to the total, or run each section with its own waste factor and sum them. If the L-shape is very irregular, sketch it on paper, divide it into the simplest rectangles possible, and run a separate calculation for each.