Concrete · 6 min read

How Much Concrete Do You Need for a 5×5 Slab?

Step-by-step volume math for a 5×5 slab, thickness tips, waste allowance, and when to use our interactive concrete calculator.

Use with our Concrete Calculator.

Pouring a small slab starts with one question: how many cubic meters (or cubic feet) of concrete do you actually need? For a 5×5 footprint, the answer depends almost entirely on thickness — not just length and width.

Quick answer for a 5×5 slab

Volume

Volume = length × width × thickness

Use the same units throughout (meters recommended).

5 m × 5 m at 100 mm (0.1 m) thick

5 × 5 × 0.1 = 2.5 m³ of concrete. Add 5–10% waste → order about 2.6–2.8 m³.

5 ft × 5 ft at 4 in (0.33 ft) thick

5 × 5 × 0.33 ≈ 8.3 cu ft. In cubic yards that's roughly 0.31 yd³ — often less than one short load.

Choosing slab thickness

  • Garden stepping paths: 75–100 mm (3–4 in)
  • Patios and light use: 100–125 mm (4–5 in)
  • Driveways: 100–150 mm (4–6 in) depending on load
  • Structural work: follow engineering specs and local code

Common mistakes

  • Entering 100 mm as “100” in a meters field (100 m slab!)
  • Forgetting the gravel base — it’s not part of concrete volume but affects prep height
  • Skipping waste — a partial pour is expensive to fix

Open interactive concrete calculator

Adjust 5×5 (or any size), thickness, and see volume + visual slab instantly.

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