How Much Does Concrete Weigh?
Weight per cubic foot, cubic yard, and slab thickness
Normal-weight concrete weighs about 150 pounds per cubic foot. That works out to roughly 4,050 pounds per cubic yard, or about 2 tons. Those two numbers explain why a half-empty dumpster of concrete can already be over its weight limit.
Concrete weight at a glance
Figures are for standard normal-weight concrete. Lightweight and high-density mixes fall outside this range; see the methodology below.
Slab weight by thickness
Most residential concrete comes out of the ground as a slab: a patio, driveway, sidewalk, or garage floor. Since concrete adds a fixed weight for each inch of thickness, you can size a slab job straight off its square footage. Every inch of thickness adds about 12.5 pounds per square foot (150 divided by 12).
| Slab thickness | Weight per sq ft | 10 × 10 patio (100 sq ft) | 20 × 20 driveway (400 sq ft) |
|---|---|---|---|
| 4 inches | 50 lbs | 5,000 lbs (2.5 tons) | 20,000 lbs (10 tons) |
| 5 inches | 62.5 lbs | 6,250 lbs (3.1 tons) | 25,000 lbs (12.5 tons) |
| 6 inches | 75 lbs | 7,500 lbs (3.75 tons) | 30,000 lbs (15 tons) |
| 8 inches | 100 lbs | 10,000 lbs (5 tons) | 40,000 lbs (20 tons) |
A 20 × 20 driveway at a standard 4-inch pour is already 10 tons. That single number decides your whole disposal plan, and it's why concrete jobs get priced by weight, not by how the pile looks.
What this means when you rent a dumpster
Broken concrete doesn't stack solid. Once it's busted into chunks, air gaps drop the packed weight to roughly 2,000 to 2,400 pounds per cubic yard in a container, versus the 4,050 of a solid yard. That still fills a weight limit fast.
Run the math against a typical container. A 20-yard dumpster often carries a 3-ton weight cap. At roughly a ton per cubic yard of rubble, you hit that cap with about 3 cubic yards loaded, and the other 17 yards of space are dead weight you can't legally use. Go over and you're paying overage fees, usually 50 to 100 dollars per ton.
We recommend the contrarian move here: for a concrete-only job, rent the smallest heavy-debris or Low-Boy container you can, not the biggest dumpster on the lot. Volume is never your constraint with concrete; weight is. A 10-yard Low-Boy rated for 10 tons that you only half-fill beats a 30-yard box you can never legally load.
Don't size a dumpster off recycling-table numbers.
Government volume-to-weight tables often list concrete near 1,400 pounds per cubic yard. That's an administrative diversion factor for mixed-load reporting, not the weight of real rubble. Broken concrete runs far heavier, and trusting the low number is how people blow past a weight cap and eat overage fees.
Where these numbers come from
The 150 pounds per cubic foot figure is the standard density for normal-weight reinforced concrete. Plain, unreinforced concrete sits closer to 145; the extra few pounds account for typical rebar, wire mesh, and absorbed moisture. We use 150 because most residential slabs and footings carry some steel, and rounding up keeps you from underestimating a load. State transportation specs put the practical range at 140 to 150 for normal-weight mixes.
- Density (150 lb/ft³): Iowa DOT Materials I.M. 340 gives 140–150 lb/ft³ for normal-weight concrete; consistent with the American Concrete Institute (ACI 318) default of 150 lb/ft³.
- Loose C&D debris factors: U.S. EPA Volume-to-Weight Conversion Factors (2016) and county C&D tables, used here only to show why diversion factors understate real rubble weight.
Estimate your project
Know the weight; now size the container. These tools do the disposal math for concrete and related demolition debris.
Common questions
How much does a cubic yard of concrete weigh?
Solid concrete runs about 4,050 pounds per cubic yard, roughly 2 tons. That's 150 pounds per cubic foot times 27. Once it's broken up and loaded in a dumpster, air gaps bring it down to about 2,000 to 2,400 pounds per cubic yard.
How much does a 4-inch slab weigh per square foot?
About 50 pounds per square foot. Each inch of thickness adds roughly 12.5 pounds per square foot, so a 6-inch slab is about 75 and an 8-inch slab about 100.
Why does concrete need a special dumpster?
Weight, not volume. A standard dumpster hits its weight cap with under 2 cubic yards of concrete, long before it looks full. Haulers use a smaller heavy-debris or Low-Boy container rated for 10 tons so the load stays legal and you skip overage fees.
Does rebar change the weight much?
Not by much. Steel is denser than concrete, but there's little of it by volume in a typical slab, so it adds a few percent at most. Rebar matters more for recycling, where magnets separate it out, than for your weight estimate.
Disclaimer: These weights are estimates for standard normal-weight concrete. Actual weight varies with mix design, moisture, aggregate, and reinforcement. For structural work, a large tear-out, or anything near a container's weight rating, confirm with your ready-mix supplier or hauler before you load.