How much does a yard of concrete weigh?
About 2 tons. A cubic yard is 27 cubic feet, and normal concrete weighs 140–150 lb per cubic foot:
| Concrete | Per cubic foot | Per cubic yard | Tons per yard |
|---|---|---|---|
| Bagged concrete mix, cured (QUIKRETE 1101) | 140 lb | 3,780 lb | 1.89 |
| Normal ready-mix | 145 lb | 3,915 lb | 1.96 |
| Reinforced concrete | 150 lb | 4,050 lb | 2.03 |
| Structural lightweight | 115 lb | 3,105 lb | 1.55 |
That's why a ready-mix truck carrying 10 yards is hauling close to 20 tons of concrete, and why a pickup can't carry even one yard. If you're mixing it yourself, a cubic yard is 45 bags of 80 lb mix — 3,600 lb of dry material plus the water.
Concrete weight per cubic foot
The calculator defaults to 145 lb per cubic foot, the planning figure our slab calculator also uses. Change it when you know more:
- 140 lb/ft³ — QUIKRETE's published cured weight for its bagged Concrete Mix.
- 150 lb/ft³ — reinforced concrete. Rebar or mesh adds a few percent of steel, and structural engineers routinely round up to 150.
- 115 lb/ft³ — structural lightweight concrete made with expanded shale or clay aggregate, used on upper floors and roof decks.
- Your own number — a ready-mix ticket or a lab report gives the exact unit weight; switch on Enter my own unit weight.
For a cylinder — a pier, a column form or a round fire-pit base — choose Cylinder and enter the diameter and height. For a pile of broken concrete you're hauling away, the tons to cubic yards converter uses the lighter weight of loose, crushed concrete instead.
Slab weight by thickness
| Thickness | Weight per sq ft | 10 × 10 ft slab | 12 × 20 ft slab |
|---|---|---|---|
| 3-1/2 in | 42.3 lb | 4,229 lb | 10,150 lb |
| 4 in | 48.3 lb | 4,833 lb | 11,600 lb |
| 5 in | 60.4 lb | 6,042 lb | 14,500 lb |
| 6 in | 72.5 lb | 7,250 lb | 17,400 lb |
| 8 in | 96.7 lb | 9,667 lb | 23,200 lb |
All at 145 lb/ft³. These numbers matter in two places: when you plan to break out and haul away an old slab (a 12 × 20 ft patio is more than five tons of debris, about two full loads in a single-axle dump truck), and when someone wants to pour a slab on a deck, a balcony or an upper floor. A 4 in slab adds 48 lb per square foot of dead load — more than most residential floors are designed to carry on top of their normal load. Get an engineer involved before pouring on anything but the ground.
Weight vs strength
A heavier mix isn't a stronger one. Strength depends on the cement content and water-cement ratio; weight depends mostly on the aggregate. That's why 4,000 psi ready-mix and 3,000 psi ready-mix weigh almost the same per yard. For a stronger slab, order the higher-psi mix and add rebar — don't simply pour it thicker.
Planning the pour itself? The slab calculator converts the same dimensions into bags or ready-mix yards, and the column calculator handles round forms and piers.
