Concrete Slab Calculator | How Much Concrete Do I Need? Mixers & Cost
Concrete slab calculator: enter length × width × thickness (or area × depth) to get m³ of concrete, how many truck mixers you need, weight and cost. Includes waste allowance and density.
How is a concrete slab calculated?
Concrete need equals the poured volume. Volume = length × width × thickness × quantity (or area × thickness). Weight = volume × density. In Türkiye, strength is ordered as Cxx/yy per TS EN 206 / TS 13515 (e.g. C30/37); normal concrete tonnage uses ≈2400 kg/m³. Truck mixers typically hold 6–12 m³ (often 9 or 12). Add 5–10% waste.
Steps
- Enter slab length, width and thickness (or area × thickness / direct m³).
- If you have several identical slabs, enter the quantity.
- Pick concrete type (C20/25–C35/45 or custom density) and waste %.
- Choose mixer capacity (6 / 8 / 9 / 10 / 12 m³) or enter it manually.
- Optionally add m³ or ton price to see cost.
TS EN 206 concrete classes (summary)
Ready-mix in Türkiye is ordered by Cxx/yy strength class. Normal concrete oven-dry density is 2000–2600 kg/m³; site tonnage commonly uses ≈2400 kg/m³:
| Class / type | Density (approx.) | Note |
|---|---|---|
| C20/25 | ≈ 2400 kg/m³ | Light slabs / general |
| C25/30 – C30/37 | ≈ 2400 kg/m³ | Most common slab / structural |
| C35/45 | ≈ 2400 kg/m³ | Higher-strength orders |
Formula
Volume (m³) = length × width × thickness × qty. With waste = volume × (1 + waste%/100). Weight (kg) = wasted volume × density. Mixers = ceil(wasted volume ÷ mixer m³).
Practical tips
- Order by strength class such as C25/30 or C30/37 (TS EN 206); density for normal mixes stays ≈2400 kg/m³.
- Floor slabs are often 10–15 cm thick; driveways need more.
- Experienced crews typically add 5–10% for waste.
- 1 m³ of normal concrete ≈ 2.4 t; mixers often carry 9 or 12 m³.
- For reinforced slabs, estimate rebar separately; this tool covers concrete volume only.
Application note
Results are guidance only. Strength class, exposure (XC, XF…), Dmax and consistency are confirmed with the quote (THBB ordering practice). Cement ≠ concrete. Mixer capacity is usable load, not total drum volume.
Rebar and total building budget
Concrete volume alone is not a project budget. For reinforcement take-off and official m² unit cost:
Frequently asked questions
How do I calculate a concrete slab?
Multiply length × width × thickness for m³. Add waste, then divide by mixer capacity and round up for how many mixers you need.
How many m³ does one concrete mixer hold?
Truck mixers typically rate 6–12 m³ of usable concrete. On Turkish sites, 9 m³ and 12 m³ are the most common. Drum geometric volume is larger than the rated load.
How many concrete mixers do I need?
Divide the wasted concrete volume by mixer capacity and round up. Example: 20 m³ with a 9 m³ mixer needs 3 mixers.
How are concrete classes written in Türkiye?
Per TS EN 206 as Cxx/yy (e.g. C30/37: cylinder 30 MPa, cube 37 MPa). Normal density is 2000–2600 kg/m³; calculations often use 2400 kg/m³.
How much does 1 m³ of concrete weigh?
About 2.4 tonnes (2400 kg/m³) for normal concrete. Lightweight (e.g. D1.8 ≈1800) weighs less; heavy (>2600) weighs more.
Is concrete the same as cement?
No. Cement is the binder paste; concrete is cement + water + sand/gravel and is far more durable.