4 × 4 ft slab: the short answer
Poured 4 inches thick (with 10% waste), a 4 × 4 ft slab needs about 5.9 cubic feet of concrete — roughly 10 × 80 lb bags, or about 0.22 cubic yards of ready-mix.
Slab size
Concrete for a 4 × 4 ft slab
A 4 × 4 ft slab poured 4 inches thick needs about 5.9 cubic feet of concrete — roughly 10 × 80 lb bags, or 0.22 cubic yards of ready-mix (includes 10% waste). Change the thickness, bag size, or shape below.
Concrete needed
—Enter dimensions to estimate concrete.
| Bags (incl. waste) | — |
|---|---|
| Ready-mix (cubic yards) | — |
| Volume (cubic feet) | — |
| Estimated cost | — |
Shopping list
Run the calculator to prepare a list.
Estimate only.
Includes your waste allowance (concrete can't be reused). Bag yields are typical for standard
mixes; confirm on the bag. Past about 1 cubic yard, ready-mix delivery is usually cheaper and
easier than mixing bags.
Before you pour
Concrete can't be reused once mixed, so the 10% allowance matters. For anything structural, confirm thickness and reinforcement with your local code. Adjust thickness and bag size in the calculator for your exact pour.
Standard volume math at 4″ with 10% waste; 80 lb bag ≈ 0.6 cu ft. Estimates only.
What a 4 × 4 ft slab is usually used for
A 4 × 4 ft slab is a small pad for a generator, AC unit, grill, statue, or a single stepping-pad base. Because it is small, most people pour it with bags, and the practical questions are mix choice, a stable subgrade, and getting one clean pour before the mix sets.
How to decide
For a pad this size, bagged mix is the normal route. The calculator assumes a 4-inch slab with 10% waste, which is a reasonable starting point for a small non-structural pad. Check the bag yield on the package — an 80 lb bag yields about 0.6 cu ft — and mix only what you can place before it begins to set.
Checks before you pour
- Compact the subgrade and consider a gravel base so the slab does not settle unevenly.
- Confirm the slab's purpose; equipment pads may need a manufacturer-specified thickness.
- Mix in batches and pour in one session so the surface finishes uniformly.
FAQ
How much concrete for a 4 × 4 ft slab?
At 4 inches thick with 10% waste, a 4 × 4 ft slab needs about 5.9 cubic feet — roughly 10 × 80 lb bags (or 14 × 60 lb), or 0.22 cubic yards of ready-mix.
Bags or ready-mix for a 4 × 4 ft slab?
At about 0.22 cubic yards this is small enough to do with bags (10 × 80 lb). For a single clean pour you could still order ready-mix, but bags are fine here.
Sources & verification
Source links and page assumptions reviewed .
- QUIKRETE: quantity calculator — Manufacturer quantity calculator and bag-yield guidance for concrete mixes.
- QUIKRETE: concrete mix data sheet — States an 80 lb bag of concrete mix yields about 0.6 cu ft at recommended consistency.
Estimate only, based on standard volume math at 4″ thickness with 10% waste. Confirm bag yield on the package and consult a pro for structural work.