Concrete Tonnage Calculator: Yards to Tons

This concrete tonnage calculator converts the volume of concrete you need (in cubic yards or cubic meters) into its weight in tons (US short tons or metric tonnes). You enter the project dimensions and the calculator returns the required tonnage, which is essential for ordering ready-mix concrete and planning delivery logistics.

Formula

The calculator uses the standard relationship between volume, density, and weight:

Weight (tons) = Volume (yd³) × Density (lb/yd³) / 2000

Where:

• Volume = Length (ft) × Width (ft) × Depth (ft) ÷ 27 (to convert cubic feet to cubic yards)
• Density = 4,050 lb/yd³ (2,400 kg/m³) — the typical density of reinforced concrete
• 2,000 = pounds per US short ton

For metric, the formula is Weight (tonnes) = Volume (m³) × Density (kg/m³) / 1000.

Worked Example

Using the default values from the calculator (length = 10 ft, width = 10 ft, depth = 4 in):

1. Convert depth to feet: 4 in ÷ 12 = 0.333 ft
2. Volume in cubic feet: 10 × 10 × 0.333 = 33.3 ft³
3. Convert to cubic yards: 33.3 ÷ 27 = 1.23 yd³
4. Weight in pounds: 1.23 × 4,050 = 4,981 lb
5. Convert to tons: 4,981 ÷ 2,000 = 2.49 US tons

The calculator shows 2.49 tons for these inputs, matching the step-by-step result.

Why Concrete Density Matters

Concrete’s density is not a fixed number. It varies with the mix design:

• Normal-weight concrete (most residential and commercial): 3,900–4,100 lb/yd³ (2,300–2,400 kg/m³)
• Lightweight concrete (used for insulation or reducing structural load): 2,500–3,000 lb/yd³ (1,500–1,800 kg/m³)
• Heavyweight concrete (used for radiation shielding): up to 6,000 lb/yd³ (3,600 kg/m³)

This calculator uses 4,050 lb/yd³, which is a safe average for standard reinforced concrete. If you are using a specialty mix, adjust the density in your own calculations — the formula remains the same.

How to Use the Calculator for Real Projects

Follow these steps for a typical slab, footing, or driveway:

1. Measure the length and width in feet (or meters).
2. Measure the depth in inches (or centimeters). For slabs, 4 inches is common; for footings, 12 inches or more.
3. Enter the values and read the volume in cubic yards — this is what you order from a ready-mix plant.
4. Use the tonnage output to estimate trucking weight or to compare with bagged concrete (each 80-lb bag yields about 0.6 ft³).

For example, a 20 ft × 30 ft driveway at 4 inches thick: volume = 20 × 30 × (4/12) ÷ 27 = 7.41 yd³. Weight = 7.41 × 4,050 = 30,010 lb = 15.0 tons. That matches what a ready-mix truck would deliver (typically 10–12 yd³ max, so this would be one full truck).

Common Mistakes and How to Avoid Them

• Mixing units: Always convert depth to feet before multiplying. A 4-inch slab is 0.333 ft, not 4 ft.
• Forgetting the 27 factor: There are 27 cubic feet in a cubic yard. Many people divide by 3, which gives a volume three times too large.
• Using the wrong density: If you use 4,050 for lightweight concrete, you’ll overestimate tonnage by about 40%.
• Ignoring waste: Order 5–10% extra for spillage, uneven subgrade, or changes in pour depth. Add this to your volume before converting to tons.

When to Use Tonnage vs. Cubic Yards

Ready-mix concrete is ordered by volume (cubic yards or cubic meters), not by weight. So why calculate tonnage? Three reasons:

• Trucking limits: Roads and bridges have weight limits. A fully loaded 10-yard truck weighs about 40 tons, so knowing the tonnage helps plan routes.
• Bagged concrete: If you’re mixing by hand, bags are sold by weight (e.g., 80 lb). Tonnage tells you how many bags you need: 1 ton = 2,000 lb = 25 bags of 80 lb.
• Recycling/disposal: When demolishing old concrete, disposal fees are often based on tonnage.

For ordering from a plant, always give the volume in cubic yards. For logistics and cost estimates, use the tonnage.

Limitations of the Calculator

This tool gives an estimate, not a precise specification. Actual concrete weight can vary due to:

• Moisture content in the aggregate
• Reinforcement steel (rebar adds about 1–2% to weight)
• Air entrainment (trapped air reduces density)
• Slump (wetter mixes may weigh slightly more)

For critical structural projects, consult the mix design from your supplier — they can provide the exact density for their specific mix. The calculator is accurate to within ±5% for standard concrete, which is acceptable for most planning purposes.

Frequently Asked Questions

How many tons is 1 cubic yard of concrete?

Using the standard density of 4,050 lb/yd³, 1 cubic yard weighs 4,050 lb, which is 2.025 US tons (1.84 metric tonnes). For lightweight concrete, it could be as low as 1.25 tons per yard.

How do I convert square feet to tons of concrete?

You can’t convert directly because you need the depth. Multiply the area (ft²) by the depth (ft) to get cubic feet, divide by 27 to get cubic yards, then multiply by 4,050 lb and divide by 2,000. For example, 100 ft² at 4 inches deep: 100 × 0.333 = 33.3 ft³ ÷ 27 = 1.23 yd³ × 4,050 = 4,981 lb = 2.49 tons.

How many 80-lb bags of concrete do I need for 1 ton?

One ton is 2,000 lb, so you need 2,000 ÷ 80 = 25 bags. However, 80-lb bags yield about 0.6 ft³ of concrete, so 25 bags give 15 ft³, which is about 0.56 yd³ — not a full yard. This is because the bag weight includes dry mix, not the final concrete weight.

Does the calculator work for metric measurements?

Yes. Switch the unit system to Metric and enter length and width in meters, depth in centimeters. The calculator will output volume in cubic meters and weight in metric tonnes (1 tonne = 1,000 kg). The density used is 2,400 kg/m³.

Why does my ready-mix order weigh more than the calculator says?

Ready-mix trucks carry water and the drum itself adds weight. Also, the delivered concrete may have a higher density if it contains more coarse aggregate. Additionally, you may have ordered extra for waste. The calculator estimates the concrete alone; the truck weight will be higher.

Is concrete heavier when wet or dry?

Fresh wet concrete is slightly heavier than fully cured dry concrete because water is part of the mix. However, most water chemically binds during curing, so the difference is small — less than 2%. The density of 4,050 lb/yd³ applies to both fresh and cured concrete for practical purposes.

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in length | Length | ft | 10 | 0
in width | Width | ft | 10 | 0
in depth | Depth | in | 4 | 0
sel unit | Unit system | US (lb/yd³)=1, Metric (kg/m³)=1
out volume_yd | Volume | yd³ | length * width * (depth / 12) / 27 | 2
out weight_lb | Weight | lb | volume_yd * 4050 | 0
out tons_us | Concrete weight | US tons | weight_lb / 2000 | 2