Concrete Slab Weight Calculator

How much does a 20x20 concrete slab weigh?

A standard 4-inch thick 20x20 slab has a volume of 133.33 ft³. Using standard concrete (150 lb/ft³), it weighs approximately 20,000 lbs, or 10 short tons. Reinforced slabs will weigh slightly more due to steel content.

What is the difference between wet and dry concrete weight?

Wet concrete is slightly heavier than dry concrete due to its water content. As concrete cures (hydrates), it retains much of that weight as chemically bound water, although some evaporation occurs. Structural calculations usually design for the 'dead load' of cured concrete.

How heavy is reinforced concrete relative to regular concrete?

Reinforced concrete is typically calculated at 156 lb/ft³, roughly 4% heavier than standard unreinforced concrete. This accounts for the high density of steel rebar or mesh embedded within the slab.

Does the slab thickness affect the density?

No, density is a material property (lb per cubic foot). However, thicker slabs result in higher volume, which directly increases the total weight proportionally.

Can I use this for pre-cast concrete sections?

Yes. As long as you know the dimensions and the specific density of the pre-cast mix (which is often higher due to compaction), this calculator will provide an accurate weight for lifting and transport planning.