The Weight of a Concrete Slab calculator estimates the weight of a rectangle (square) concrete slab. 
INSTRUCTIONS: Choose units and enter the following:
- (L) Length of slab.
- (W) Width of slab.
- (D) Depth of a slab.
- (mD) Mean Density of Concrete (default: 2450 kg/m3) The following are approximates of different grades of concrete.
- M20, M25 and M30 concrete have densities of 2550 kg/m3
- M60 (high grade) has a density of 2800 kg/m3
- M80 and M100 (ultra high strength) have densities of 2960 kg/m3
- Plain concrete 2450 kg/m3
Weight of a Slab (Wt): The calculator returns the weight of the slab in pounds. However, this can be automatically converted to other mass or weight units (e.g. short tons or metric tons) via the pull-down menu. The calculator also returns the volume (V) of concrete and the surface area (A). To compute the weight and materials for a concrete countertop, CLICK HERE.
Note: This is the weight of a slab with just concrete. The presence of rebar causes additional rebar weight. The Rebar and Concrete in a Slab calculator computes the:
- Total Length of rebar in feet
- Total Weight of rebar in pounds, and
- Total Volume of concrete in cubic yards. Note: this accounts for the concrete displaced by rebar.
- Total Weight of Slab in pounds. Note: this includes the weight of rebar and concrete.
The Math / Science
The weight of a concrete slab can be estimated by computing the volume of the slab and multiplying the volume (V) by the density of the concrete. The volume is simply the area (A = L*W) times the depth (D).
The formula for the weight of a slab used in this calculator is:
Wt = L•W•D•mD
where:
- Wt = Total Weight of slab
- L = Length of slab
- W = Width of Slab
- D = Depth of Slab
- mD = Mean Density of Concrete (2400 kg / m³). The density of Lightweight concrete is approximately 1,794 kg/m3.
This calculation does NOT include the weight of rebar. To compute the weigh of a slab with rebar, see the Weight of a Slab with Rebar Calculator. The Weight of a Slab with Rebar Calculator computes the weight of rebar in the rectangular slab, and removes the weight of the displaced concrete to provide the best estimate.
Rebar and Slab Calculators:
- Rebar Calculator (Spanish Version: Calculadora de Barras de Refuerzo)
- Weight of Any Volume of Concrete
- Rebar and Concrete Volume and Weight in a Slab
- Rebar Weight
- Length of Rebar needed for a slab.
- Weight of Rebar in a slab.
- Weight, Volume of Concrete and Surface Area of a Concrete Slab
- Surface Area of a slab
- Surface Area of Concrete Forms.
- Volume of Concrete in a slab.
- Water Needed for Concrete
- Rebar and Concrete in a Slab
- Length of Rebar in Grid
- Weight of Rebar in Grid
- Rebar in a Wall
- Rebar in an Irregular Shaped Slab
- Rebar in a Circular Slab
- Rebar Lapping Length
- Rebar Cost Estimate
- Weight of Length of Rebar
- Concrete Displaced by Rebar
- Total Weight of a Slab with Rebar