Contractor Calculator · Concrete
Concrete Slab Cost Calculator: Yards, Bags, and Price
Concrete is sold by the cubic yard, so concrete slab cost is a volume question. Set the slab below; yards, bags, and dollars update as you type.
Pricing the whole job? Estimate it from a photo in about six seconds.
Published range, updated Aug 27, 2026, from published averages of $160 to $180 per cubic yard. Local prices vary.
How the concrete slab cost calculator works
The math is three moves. Multiply length by width by thickness in feet for cubic feet. Divide by 27 for cubic yards. Multiply by the price per yard.
Thickness trips people because it is measured in inches. Divide by 12 first. A 4 in slab is 0.333 ft, so each square foot of slab is a third of a cubic foot.
The calculator adds waste and rounds the order up to the next quarter yard. NRMCA CIP 31 says to order 4% to 10% over the plan quantity for spillage, uneven subgrade, and over-excavation. Coming up short means a second delivery and a cold joint.
Worked example: a 12 by 12 patio at 4 inches
Area is 144 sq ft. At 0.333 ft thick that is 48 cu ft, or 1.78 cubic yards. Add 10% waste for 1.96, round up, and order 2 cubic yards.
At the published national averages of $160 to $180 per cubic yard, the concrete runs $320 to $360. That is material only; base, forms, reinforcement, labor, and finishing are separate lines.
SimplyWise Cost Estimator prices all of those lines from a photo in about 6 seconds.
Common slab sizes at a glance
All rows: 4 in thick, 10% waste, order rounded up to the quarter yard, national material range.
| Slab | Volume | Order | 80 lb bags | Material cost |
|---|---|---|---|---|
| 10 by 10 | 1.23 cu yd | 1.50 cu yd | 62 | $240 to $270 |
| 12 by 12 | 1.78 cu yd | 2.00 cu yd | 88 | $320 to $360 |
| 16 by 20 | 3.95 cu yd | 4.50 cu yd | 196 | $720 to $810 |
| 20 by 20 | 4.94 cu yd | 5.50 cu yd | 245 | $880 to $990 |
| 24 by 24 | 7.11 cu yd | 8.00 cu yd | 352 | $1,280 to $1,440 |
| 30 by 30 | 11.11 cu yd | 12.25 cu yd | 550 | $1,960 to $2,205 |
At 6 in, common for garages, every number rises by half again. The 24 by 24 order becomes 11.75 yards instead of 8.
What drives the price per yard
NRMCA put the average 2023 selling price at $160 per cubic yard, on 400 million cubic yards delivered. Producers in its benchmarking survey ranged from about $150 to $171 per yard, so identical mixes price differently plant to plant.
Prices have climbed. An index of four large public producers rose from $113 per yard in 2016 to $180 in 2025, skewing commercial. Those two anchors, $160 and $180, are the range this page uses.
What moves a local quote: mix strength, distance, and load size. Mixers carry 8 to 12 cubic yards per CIP 31, and it warns against ordering small cleanup loads. Quote the yard locally; the volume math holds.
Turn the yards into a quote
The calculator prices the concrete; the job has six more lines. SimplyWise Cost Estimator turns a photo into an itemized estimate in about 6 seconds. Pricing is $29.99/mo or $239.99/yr, about $20/mo on annual, with a 7-day free trial.
Bags or a truck
QUIKRETE and Sakrete both publish an 80 lb bag at 0.60 cu ft, so a cubic yard is 45 bags; a 60 lb bag at 0.45 cu ft is 60. The 12 by 12 patio is 88 bags with waste, 7,040 lb through a mixer one bag at a time.
Bags win small work: post runs, a condenser pad, repairs. Past about a yard, the truck wins on your back before anything else.
Run the estimate in this order
-
Measure the pour, not the patio
Length, width, thickness. Thickness moves the total fastest, so confirm it against the plan first.
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Add waste before you order
CIP 31 calls for 4% to 10% over plan. Uneven subgrade eats concrete you cannot see.
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Get two plant quotes per yard
The national range brackets the market. A local quote typed into the calculator reprices the order exactly.
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Put the whole job on paper
Concrete is one line. Base, forms, steel, labor, and finish are the rest of the estimate the customer signs.
Keep reading
Sources
- NRMCA CIP 31, Ordering Ready Mixed Concrete (4% to 10% over plan; trucks 8 to 12 cu yd; verified 2026-08-27).
- NRMCA, Performance Benchmarking Survey and State of the Industry (2023 average $160 per cu yd; quartiles $150.03 to $170.66; verified 2026-08-27).
- Concrete Financial Insights, US Concrete Industry Data (large-producer index $113.08 in 2016 to $179.95 in 2025; verified 2026-08-27).
- QUIKRETE Concrete Mix, data sheet No. 1101 (80 lb yields 0.60 cu ft; 60 lb 0.45; verified 2026-08-27).
- Sakrete, High-Strength Concrete Mix (same published yields: 80 lb 0.6 cu ft, 60 lb 0.45; verified 2026-08-27).
- SimplyWise Cost Estimator, App Store (4.8 rating; verified 2026-08-22).
Common questions on slab pricing
How much does a 12 by 12 concrete slab cost?
Order 2 cubic yards at 4 in thick with 10% waste. National averages of $160 to $180 per cubic yard put the concrete at $320 to $360, before base and labor.
How many yards of concrete for a 24 by 24 slab?
At 4 in thick the slab holds 7.11 cubic yards. With 10% waste you order 8. At 6 in, common for garages, the order is 11.75.
How much does a 30 by 30 slab cost?
At 4 in thick the order is 12.25 cubic yards, or $1,960 to $2,205 in concrete at the national averages. Mixers carry 8 to 12 yards, so plan on two trucks.
How many 80 lb bags of concrete make a cubic yard?
45. QUIKRETE and Sakrete both list an 80 lb bag at 0.60 cu ft, and 27 divided by 0.60 is 45. A 60 lb bag runs 60 to the yard.
Does the calculator include labor or base prep?
No. It prices the concrete from published national averages. Excavation, base, forms, reinforcement, labor, and finishing are local lines on the full estimate.
Can SimplyWise price a concrete slab from a photo?
Yes. SimplyWise Cost Estimator turns a photo into an itemized estimate in about 6 seconds. Free to try, at $29.99/mo or $239.99/yr.
Turn the pour into a signed quote.
Snap a photo and get an itemized estimate in about 6 seconds. Free to try.