Concrete Weight Calculator: Estimate Slab and Piece Weight
This concrete weight calculator turns dimensions into weight. Enter length, width, and thickness of a slab or piece, choose a concrete type like normal or lightweight, and set how many you have. The tool returns volume, weight per piece, total weight in pounds, kilograms, tons, and tonnes, plus material cost by weight. It’s a quick way to plan transport, formwork, or a material budget.
Concrete weight catches people off guard. A cubic foot of normal concrete tips the scale at about 145 pounds. A cubic yard? That’s nearly two tons. Knowing the weight matters when you’re planning a pour, sizing a truck, or checking whether a structure can carry the load. This concrete weight calculator uses the dimensions of your slab or piece and the density of the mix to produce an accurate weight estimate. Choose from normal, lightweight, heavyweight, high-density, or aerated concrete, or enter a custom density. The output covers volume, weight per piece, total weight in pounds, kilograms, US tons, and metric tonnes. Add a price per unit weight and you’ll get a material cost, too. It’s built for contractors, estimators, and anyone who needs to know what concrete actually weighs before it shows up on site.
How to Use the Concrete Weight Calculator
Pick your currency from the top dropdown.
Enter the length, width, and thickness of one piece. Set the unit for each.
Choose the concrete type. Normal weight is the default.
Adjust the density if you pick Custom or need a specific mix.
Set the waste factor. Five percent is a good default.
Enter how many pieces you have.
Add your price per unit weight and any additional cost.
Review the Summary tab for total weight, or switch to Detailed Breakdown for every intermediate value.
How the Concrete Weight Calculator Formula Works
Weight comes from volume multiplied by density. Everything else is unit conversion and cost scaling.
Formula: Volume = Length × Width × Thickness (all in feet)
Formula: Total weight = Volume × Number of pieces × Density × (1 + Waste %)
Formula: Material cost = Total weight (lbs) × Price per lb
Density is the key input. The tool ships with presets for normal weight (145 lb/ft³), lightweight (115), heavyweight (190), high-density (250), and aerated concrete (60). Pick Custom and you can type any number you want. Density units convert to lb/ft³ before the math runs, so kg/m³ and lb/yd³ both work.
Price per unit weight converts to per lb before calculating. If you enter $0.05 per kg, the tool converts that to about $0.0227 per lb and multiplies by total weight. The Additional Cost field adds a flat dollar amount on top.
If any dimension is zero or blank, the results clear. There’s no upper bound on inputs, so a very large piece returns a very large number. Waste applies to volume, then flows through to weight and cost.
Worked Example: A 12 ft × 8 ft Slab, 5 Inches Thick
Say you’re pouring a slab 12 ft long, 8 ft wide, and 5 inches thick. Normal weight concrete. Waste factor is 5%. Price is $0.06 per lb.
Thickness in feet: 5 ÷ 12 = 0.4167 ft
Volume per piece: 12 × 8 × 0.4167 = 40.00 ft³
Density: 145 lb/ft³
Weight per piece: 40.00 × 145 = 5,800 lbs
With 5% waste: 40.00 × 1.05 = 42.00 ft³
Total weight: 42.00 × 145 = 6,090 lbs (2,762 kg)
US tons: 6,090 ÷ 2,000 = 3.045 tons
Metric tonnes: 2,762 ÷ 1,000 = 2.762 tonnes
Material cost: 6,090 × $0.06 = $365.40
That’s just over three US tons for a slab that fits in a small backyard. If you were planning to move it, you’d need a machine, not a wheelbarrow. The cost estimate covers material by weight only. It doesn’t include delivery, labor, or reinforcement.
