Concrete Weight Calculator
A concrete weight calculator multiplies length × width × thickness in feet by 150 lb/ft³. A 10 × 10 ft slab at 4 in weighs 5,000 lb, or 2.5 tons.
Concrete weight calculator: the formula
This concrete weight calculator finds volume as length × width × (thickness in inches ÷ 12), in cubic feet, then multiplies by the density to get pounds. Dividing by 2,000 gives US tons, and dividing the cubic feet by 27 gives cubic yards. The density defaults to 150 lb per cubic foot, the usual figure for normal-weight concrete, and you can change it.
A 10 × 10 ft slab, 4 inches thick, is 33.3 cubic feet and weighs 5,000 lb.
Why weight matters
You need the weight when you plan to lift, haul, or support concrete. That includes:
- Booking a dumpster or truck for demolition.
- Checking whether a trailer can carry precast pieces or bags.
- Estimating the dead load a slab puts on a structure below.
- Sizing a crane or forklift for a precast step or wall block.
The same slab can be described three ways: by volume in cubic yards for the ready-mix order, by weight in pounds for the trailer, and by tons for the hauler. This tool shows all three from one set of measurements.
Worked examples
- The default: 10 × 10 ft slab, 4 in thick
- Thickness in feet: 4 ÷ 12 = 0.333 ft
- Volume: 10 × 10 × 0.333 = 33.33 ft³
- Weight: 33.33 × 150 = 5,000 lb
- Tons: 5,000 ÷ 2,000 = 2.50 tons
- Volume in yards: 33.33 ÷ 27 = 1.23 yd³
- Patio tear-out: 12 × 12 ft, 6 in thick
- Volume: 12 × 12 × 0.5 = 72 ft³
- Weight: 72 × 150 = 10,800 lb, or 5.40 tons
- Volume: 2.67 yd³ of solid concrete
Many dumpster rentals include a weight allowance and charge for anything over it. A load like this can exceed what a small bin allows, so ask the hauler before you book.
- Same 10 × 10 ft slab in lightweight concrete at 110 lb/ft³
- 33.33 × 110 = 3,667 lb, or 1.83 tons
Concrete density reference
| Concrete type | Typical density (lb/ft³) | Weight per yd³ |
|---|---|---|
| Normal-weight, reinforced (planning figure) | 150 | 4,050 lb |
| Normal-weight, plain | About 145 | About 3,915 lb |
| Structural lightweight | About 90–115 | About 2,430–3,105 lb |
| Heavyweight (radiation shielding) | Much higher; depends on aggregate | Check the mix design |
Weight per square foot by thickness
| Thickness | lb per sq ft at 150 lb/ft³ | 100 sq ft weighs |
|---|---|---|
| 2 in | 25 | 2,500 lb |
| 3 in | 37.5 | 3,750 lb |
| 4 in | 50 | 5,000 lb |
| 5 in | 62.5 | 6,250 lb |
| 6 in | 75 | 7,500 lb |
| 8 in | 100 | 10,000 lb |
Thickness drives weight in straight proportion. Every extra inch adds 12.5 lb to each square foot.
How to measure
- Slabs: measure length and width in feet, and thickness at several edges. Old slabs are often thicker or thinner than you expect.
- Footings and walls: use the same three dimensions; enter the wall height as length, the wall length as width, and its thickness in inches.
- Round items: for piers and columns, find the volume with the sonotube calculator, then multiply cubic feet by 150.
- Steps: break them into rectangular blocks and add the weights.
Mistakes to avoid
- Using thickness in feet in the inch box. Entering 0.33 instead of 4 makes the answer 12 times too small.
- Confusing tons. The result is in US short tons of 2,000 lb. A metric tonne is about 2,205 lb. Convert with the pounds to tons calculator.
- Judging haul volume from weight. Broken concrete takes up more room than the slab did, so a truck may fill up by volume before it reaches its weight limit.
- Forgetting the rebar. Plan heavy-reinforced pieces at 150 or more. The rebar weight calculator gives the steel separately.
For loads on a floor or roof, the dead load calculator adds concrete to other materials. Anything you plan to suspend or support should be checked by a licensed structural engineer.
Weights are estimates from typical densities. Real weight varies with mix design, aggregate, and moisture.
Frequently asked questions
How much does a cubic yard of concrete weigh?
At 150 lb per cubic foot, a cubic yard is 27 × 150 = 4,050 lb, or just over 2 tons. Wet ready-mix in the truck is close to this. Lightweight concrete can be roughly 90 to 115 lb per cubic foot, so a yard of it weighs far less.
Why is 150 pounds per cubic foot used for concrete?
Normal-weight concrete made with ordinary sand and stone usually lands near 145 to 150 lb per cubic foot, and 150 is the standard planning figure, especially for reinforced concrete. The density box is editable, so enter 145 for plain concrete or your lightweight mix's value.
How much does a 4 inch concrete slab weigh per square foot?
A 4 inch slab is one third of a foot thick, so each square foot holds 0.333 cubic feet. At 150 lb per cubic foot, that is 50 lb per square foot. A 6 inch slab is 75 lb per square foot.
How much will old concrete weigh when I haul it away?
Broken concrete weighs the same as it did in the slab, but it takes up more space because of the gaps between chunks. Use the slab size here for the weight, then check your dumpster's weight limit. A 12 × 12 ft patio at 6 inches is about 10,800 lb, or 5.4 tons.
Does rebar change the weight much?
Only slightly in most slabs. Steel is about 490 lb per cubic foot, but rebar fills a small share of the volume. Using 150 rather than 145 lb per cubic foot is the usual way to allow for normal reinforcement.
Estimates only. Verify quantities with your supplier before purchasing.