How Much Does a Yard of Concrete Weigh? Pounds, Tons and Slab Weight

A cubic yard of plain concrete weighs about 4,050 pounds, or 2.025 short tons, at 150 lb per cubic foot. With reinforcement, WSDOT uses 155 lb per cubic foot, or 4,185 lb per yard. Fresh concrete varies with air and aggregate.

A 10 × 12 ft slab, 4 in thick, holds 40 cubic feet and weighs 6,000 lb, or 3 short tons. The 44 cubic feet you would order with a 10% allowance weigh 6,600 lb.

How do you calculate how much concrete weighs?

weight (lb)  = volume (cu ft) × density (lb per cu ft)
volume (cu ft) = volume (cu yd) × 27
short tons   = pounds ÷ 2,000
kilograms    = pounds × 0.45359237
plain concrete:      150 × 27 = 4,050 lb per cu yd
reinforced concrete: 155 × 27 = 4,185 lb per cu yd

1. Get the volume in cubic feet. For a slab, that is length × width × thickness in feet. How to calculate cubic yards covers other shapes, and one cubic yard is 27 cubic feet.
2. Multiply by the density: 150 lb per cubic foot for plain concrete, or 155 for reinforced.
3. Divide by 2,000 for short tons, the US construction ton.

Density is weight per unit of volume, so the same formula works in either direction: divide a known weight by 150 to get cubic feet. For tons to cubic yards across gravel, sand and soil, see how many cubic yards are in a ton.

Should you use 150 or 155 pounds per cubic foot?

Washington State DOT’s Bridge Design Memo 05-2010 lists 150 lb per cubic foot for plain concrete and 155 lb per cubic foot for dead load with reinforcement. This guide uses 150 as the default and shows 155 beside it. The steel in rebar and mesh is denser than concrete, so a heavily reinforced pour weighs a bit more per cubic foot than a plain one. Both are planning values from a bridge-design table, not a property of every mix.

Fresh concrete varies with air content and aggregate, so a specific mix can land above or below these numbers. The batch ticket from your supplier is the weight for your mix. The 5 lb gap is 3.3% of 150, so for a quick estimate the choice rarely changes a plan.

How much does 1, 2, 5 or 10 cubic yards of concrete weigh?

Each row is the volume times the density. The short-ton columns divide the pounds by 2,000.

To size a delivery or a haul, multiply the cubic yards by 4,050 and compare the result with the payload rating of your truck or trailer. This guide has no payload figures: check the rating for your vehicle.

How much does a concrete slab weigh per square foot?

A slab one square foot in area and T inches thick holds T ÷ 12 cubic feet, so its weight is 150 × T ÷ 12 pounds. Thicknesses of 4, 5 and 6 inches give the figures below.

Per 100 sq ft, a 4 in slab is 100 × 4 ÷ 12 = 33.33 cubic feet, or 1.23 cubic yards. The reinforced column uses 155 lb per cubic foot, so a 4 in slab is 155 ÷ 3 = 51.7 lb per square foot. The thickness a slab needs depends on its use, the soil and local code, and is not a weight question.

How much does a bag of concrete weigh once it is mixed?

The number on the bag is the dry weight. Mixed with water, the bag yields a known volume, and that volume at 150 lb per cubic foot is heavier than the dry mix. The yields below are from the QUIKRETE Concrete Mix No. 1101 data sheet.

For every size, the finished concrete comes out 12.5% heavier than the dry bag, because water is added to the mix. Wet weight here is arithmetic on the default density, not a figure from the data sheet, so treat it as an estimate. To count bags for a volume, see how many bags of concrete you need. For the weight and bag count of a delivered pallet, see how many bags of concrete are on a pallet.

Worked examples: a new slab and a slab to demolish

Example 1: a new 10 × 12 ft slab, 4 in thick.

• Volume: 10 × 12 × (4 ÷ 12) = 40 cubic feet, which is 40 ÷ 27 = 1.4815 cubic yards.
• Weight, plain: 40 × 150 = 6,000 lb, which is 6,000 ÷ 2,000 = 3.0 short tons, or 6,000 × 0.45359237 = 2,721.55 kg.
• Weight, reinforced: 40 × 155 = 6,200 lb, or 3.1 short tons.
• With a 10% allowance: 40 × 1.10 = 44 cubic feet, and 44 × 150 = 6,600 lb, or 3.3 short tons. This is the concrete you order, not the slab you pour.

Example 2: how heavy is a 20 × 20 ft slab you plan to break out? It is 4 in thick, plain concrete.

• Area: 20 × 20 = 400 sq ft. Volume: 400 × (4 ÷ 12) = 133.33 cubic feet, or 4.94 cubic yards.
• Weight: 400 × 50 = 20,000 lb, which is 10 short tons, or 20,000 × 0.45359237 = 9,071.85 kg.
• With mesh or rebar counted at 155: 133.33 × 155 = 20,667 lb, or 10.33 short tons.

Broken concrete takes up more space than the intact slab, so the weight is reliable and the pile size is not. Ask your hauler or disposal site how they charge, by the ton or by the load, and what they accept.

How many short tons, kilograms and tonnes is a yard of concrete?

• Short tons: 4,050 ÷ 2,000 = 2.025. A short ton is 2,000 lb, the ton used in US construction.
• Kilograms: 4,050 × 0.45359237 = 1,837.05 kg, which is 1.84 metric tonnes. A metric tonne is 1,000 kg.
• Per cubic meter: 150 lb per cubic foot × 16.01846337 = 2,402.8 kg per cubic meter.
• Long tons: a long ton is 2,240 lb, used in the UK, so 4,050 lb is 1.81 long tons.
• Reinforced: 4,185 lb is 2.0925 short tons, or 1,898.28 kg.

These are the NIST Handbook 44 definitions. When a quote or a spec says “tons”, check which one. For how a ton converts to cubic yards, a plain concrete ton is 2,000 ÷ 150 = 13.33 cubic feet, or 0.49 cubic yards.

Assumptions, common errors and limits

• The figures use 150 lb per cubic foot for plain and 155 for reinforced concrete. Lightweight and heavyweight mixes, high air content and unusual aggregates change the density, and the supplier’s batch ticket is the weight for your mix.
• Confusing cubic yards with tons. A yard is volume and a ton is weight. One cubic yard of concrete is 2.025 short tons, not one.
• Using the dry bag weight for the finished concrete. Add the mixing water: an 80 lb bag makes about 90 lb of concrete at 150 lb per cubic foot.
• Weighing the order instead of the pour. An allowance adds concrete you buy, not weight in the slab.
• Mixing tons. A short ton, a long ton and a metric tonne are three different weights.
• Weight here is a quantity estimate for planning a haul or a disposal. The dead load of a slab, a deck or a wall on a structure, bearing, and the load rating of a truck, trailer, lift or floor belong to an engineer and the manufacturer’s rating. This guide does not size any of them.
• Wet concrete is caustic and can burn skin. Wear gloves and eye protection when you handle it.

Common questions