How much does a cubic yard of concrete weigh?

A cubic yard of normal-weight concrete weighs approximately 3,900–4,050 pounds (about 2 tons). This is based on a density of 145 pounds per cubic foot × 27 cubic feet per yard = 3,915 lbs.

How much does a cubic foot of concrete weigh?

Normal-weight concrete weighs approximately 145 pounds per cubic foot (2,320 kg/m³). Lightweight concrete weighs about 90–115 lb/ft³, and heavyweight concrete can weigh over 200 lb/ft³.

How much does an 80 lb bag of concrete weigh when mixed?

An 80 lb bag of dry concrete mix weighs 80 pounds. When mixed with water, the wet concrete weighs slightly more (about 87–90 lbs), but the cured concrete weighs approximately 85–87 lbs after water evaporates during curing.

How much does a concrete slab weigh?

A 10×10 ft slab at 4 inches thick contains 33.3 cubic feet of concrete. At 145 lb/ft³, that weighs approximately 4,830 pounds (2.4 tons). A 20×20 slab at 6 inches thick weighs about 29,000 pounds (14.5 tons).

Does concrete get lighter as it cures?

Concrete loses a small amount of weight as it cures because water evaporates during the hydration process. A typical mix loses about 3–5% of its wet weight over the first 28 days. However, for structural calculations, engineers use the cured density of 145 lb/ft³ (3,915 lbs per cubic yard) as the standard.

How much does a concrete driveway weigh per square foot?

A 6-inch concrete driveway weighs approximately 72.5 pounds per square foot (145 lb/ft³ × 0.5 ft). A 4-inch slab weighs about 48.3 lbs per square foot. These numbers matter for structural applications — for example, a 400 sq ft patio at 4 inches thick adds approximately 19,300 lbs (9.65 tons) of dead load to the soil below. This is why a well-compacted subgrade and adequate gravel base are essential: the soil must support this load without settling.

Why does concrete density matter for engineering?

Concrete density (unit weight) is a fundamental input in structural engineering calculations. Engineers use it to calculate dead loads (the weight of permanent structural elements), which drives the sizing of beams, columns, and foundations. The standard value of 145 lb/ft³ (2,320 kg/m³) is specified by ACI 318 for normal-weight concrete. Lightweight and heavyweight concrete mixes have different densities and require adjusted calculations — always confirm the mix density with your supplier for non-standard applications.

Concrete Weight Calculator — Pounds, Tons & Kilograms

Estimates the total weight of concrete for any pour volume — accounting for mix density.

How to Use This Concrete Weight Calculator

This concrete weight calculator converts a volume of concrete — in cubic yards, cubic feet, or cubic meters — to weight in pounds, short tons, and kilograms. Enter your volume in any unit to get the equivalent weight instantly. To find the volume first, use our concrete calculator.

Why Concrete Weight Matters for Your Project

Knowing the weight of a concrete pour has practical implications beyond structural engineering. A typical ready-mix truck carries 8–10 cubic yards — approximately 31,000–39,000 lbs of concrete alone. That weight, combined with the truck itself (up to 66,000 lbs gross vehicle weight), can damage driveways, lawns, and soft soil. Before ordering, confirm the truck can access your site without crossing over septic systems, underground utilities, or weak surfaces.

For new slabs, the weight of the concrete dead load must be supported by the soil below. Standard undisturbed soil has a bearing capacity of 1,500–3,000 lbs per square foot — well above the 48–72 lbs per square foot that a residential slab imposes. However, loose fill, expansive clay, or poorly compacted subgrade may have much lower bearing capacity and can cause differential settlement and slab cracking. A 4-inch compacted gravel base improves both drainage and load distribution.

How Much Does Concrete Weigh?

Normal-weight concrete has a density of approximately 145 pounds per cubic foot (2,320 kg/m³). This is the standard density used in structural engineering and is what most ready-mix concrete suppliers deliver.

1 cubic foot of concrete = 145 lbs
1 cubic yard of concrete = 3,915 lbs (about 2 short tons)
1 cubic meter of concrete = 2,320 kg (2.32 metric tons)

Concrete Weight by Common Project Size

10×10 slab at 4 in thick (1.23 yd³) — approximately 4,814 lbs (2.4 tons)
20×20 driveway at 6 in thick (7.4 yd³) — approximately 28,970 lbs (14.5 tons)
Single 80 lb bag mixed — approximately 85–87 lbs cured

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Types of Concrete and Their Densities

Not all concrete weighs the same. The type of aggregate used determines the final density:

Normal-weight concrete — 140–150 lb/ft³ (2,240–2,400 kg/m³) — standard mix with sand and gravel aggregate
Lightweight concrete — 90–115 lb/ft³ (1,440–1,840 kg/m³) — uses expanded shale, clay, or slate aggregate; used to reduce structural loads
Heavyweight concrete — 180–250 lb/ft³ (2,880–4,000 kg/m³) — uses dense aggregates like barite or magnetite; used for radiation shielding

This calculator uses the standard 145 lb/ft³ value for normal-weight concrete. If you are using a specialty mix, adjust your estimate accordingly.

Concrete Weight by Project Size

Understanding how much your pour will weigh helps with logistics planning, equipment rental, and structural design. Here are real-world weights for common residential and commercial projects using standard 145 lb/ft³ concrete:

Sidewalk (4 ft × 30 ft × 4 in) — 1.48 yd³ = approximately 5,800 lbs (2.9 tons)
Patio slab (12 ft × 16 ft × 4 in) — 2.37 yd³ = approximately 9,280 lbs (4.6 tons)
Two-car driveway (20 ft × 40 ft × 6 in) — 14.81 yd³ = approximately 58,000 lbs (29 tons)
Garage floor (24 ft × 24 ft × 5 in) — 8.89 yd³ = approximately 34,800 lbs (17.4 tons)
Basement slab (30 ft × 40 ft × 4 in) — 14.81 yd³ = approximately 58,000 lbs (29 tons)

A standard ready-mix truck carries about 10 cubic yards (39,150 lbs of concrete). Any pour over 10 yd³ will require multiple truck loads — plan your pour schedule accordingly. To calculate the volume for your specific project, use our concrete yard calculator.

Why Concrete Weight Matters

Knowing the weight of your concrete pour is essential in several situations:

Structural design — engineers calculate dead loads (the weight of permanent building elements, including concrete) to size beams, columns, and foundations
Transportation planning — a ready-mix truck carries 8–10 cubic yards, weighing 31,000–39,000 lbs of concrete alone, plus the truck weight; bridge and road weight limits must be confirmed
Equipment selection — cranes, forklifts, and scaffolding have maximum safe working load ratings; never exceed them when moving precast concrete elements
Subgrade and slab-on-grade design — the weight of a concrete slab must be supported by the soil beneath it; poor subgrade requires a thicker gravel base or additional soil improvement. Use our concrete slab calculator to determine the exact volume and weight of your slab.

Sources & References

ACI 318-19: Building Code Requirements for Structural Concrete — American Concrete Institute
PCA: Design and Control of Concrete Mixtures (16th Edition) — Portland Cement Association
ASTM C94/C94M: Standard Specification for Ready-Mixed Concrete — ASTM International

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Concrete Weight Calculator