Concrete Volume Calculator

Foundation type × dimensions + waste factor → concrete volume + rebar weight + remicon truck count.

Result

Enter foundation dimensions.

What this tool does

The Concrete Volume Calculator computes pour volume for two foundation types common in light-frame construction: Strip Footings and Mat Slabs. Enter width, depth (or thickness), and length to get net volume, waste-adjusted order volume (default 5% waste), a quick rebar estimate (default 90 kg/m³ for residential strip footings), and the number of ready-mix trucks based on the Korean standard 6 m³ per truck. It is designed to catch ordering errors before concrete is dispatched to site.

Who uses this

Pre-order check for ready-mix quantity and truck count before timber-frame house foundation work
Concrete volume takeoff for small sheds, farm buildings, or container pads
Side-by-side comparison of different slab thicknesses to balance cost vs strength
Cross-checking a contractor's concrete quote against your own calculation
Quick rebar weight estimate for preliminary steel budget

How to Use (4 Steps)

1Select foundation type. Choose 'Strip Footing' for a continuous wall footing, or 'Mat Slab' for a flat slab covering the entire footprint.
2Enter width (m), depth or thickness (m), and length (m). For strip footings, depth is the vertical dimension below grade. For mat slabs, thickness is the slab depth.
3Adjust waste factor (%). The default 5% covers typical pour loss and form leakage on straightforward sites. Increase to 10% for uneven terrain or complex formwork.
4Check or adjust rebar density (kg/m³). The default 90 kg/m³ is a rule-of-thumb for residential strip footings with D10–D13 double-layer rebar. Review the results: adjusted volume (m³), rebar weight (kg), and ready-mix truck count.

Formulas & References

■ Net Volume V_raw = width (m) × depth or thickness (m) × length (m) ■ Waste-Adjusted Volume V_adj = V_raw × (1 + waste % / 100) Default waste: 5% (max 30%) ■ Rebar Weight (quick estimate) W_rebar = V_adj × rebar density (default 90 kg/m³) Note: Rule-of-thumb for residential footings only. Use structural drawings for permitted buildings. ■ Ready-Mix Truck Count N_truck = V_adj ÷ 6 m³ Korean standard drum mixer: 6 m³ capacity (KS F 4009 convention) Result is shown as a decimal — round up when placing order

Worked Examples

Example 1: Farm cabin strip footing (10 m × 0.4 m × 0.3 m)

Width 0.4 m, depth 0.3 m, length 10 m → net volume 1.2 m³. With 5% waste: 1.26 m³. Truck count: 0.21 (order 1 truck — check minimum order with supplier). Rebar at 90 kg/m³: ≈ 113 kg.

Example 2: Timber-frame house mat slab (8 m × 10 m, 150 mm thick)

Width 8 m, thickness 0.15 m, length 10 m → net volume 12 m³. With 5% waste: 12.6 m³. Truck count: 2.1 (order 3 trucks to cover 12.6 m³ across two loads). Rebar at 90 kg/m³: ≈ 1,134 kg. Cross-check with structural engineer's rebar schedule before ordering.

Example 3: 4 isolated column pads (each 0.6 m × 0.4 m × 0.6 m)

Single pad: 0.6 × 0.4 × 0.6 = 0.144 m³. To total 4 pads, enter length as 2.4 m (0.6 × 4) or multiply result by 4 manually. Total with 5% waste: ≈ 0.605 m³. Minimum ready-mix order in Korea is typically 3 m³ — coordinate pour timing with other work.

Frequently asked questions

Should I use 5% or 10% waste?

5% covers flat, simple sites with tight formwork. Use 7–10% for uneven ground, complex footing shapes, or whenever you are unsure. Running short after the truck leaves is expensive — when in doubt, add more waste factor.

Is one Korean ready-mix truck exactly 6 m³?

The standard agitator truck drum holds 6 m³ of mixed concrete. Some larger trucks carry 7–8 m³. This tool uses 6 m³ as the baseline. Always confirm the actual truck capacity with your ready-mix supplier before placing the order.

Is the calculation formula different for strip footings vs mat slabs?

The formula is identical: V = width × dimension × length. The difference is terminology — for strip footings the middle dimension is 'depth' (vertical below grade), for mat slabs it is 'thickness' (slab depth from top to bottom).

What does the 90 kg/m³ rebar density represent?

It is a rule-of-thumb mid-point for residential strip footings reinforced with D10–D13 bars in a double grid (typical range 80–100 kg/m³). If you have structural drawings, use the rebar schedule instead — that will be far more accurate. Treat this tool's rebar output as a budget placeholder only.

Does this calculator handle concrete mix design (strength grade)?

No. This tool focuses on volume and rebar weight only. Specify concrete compressive strength (e.g., 21 MPa, 24 MPa) separately when ordering from a ready-mix plant. For most residential foundations in Korea, 21–24 MPa (fck) is standard. Check the structural general notes on your drawings.

How do I calculate L-shaped or T-shaped footings?

Split the cross-section into rectangular segments, calculate each segment separately, and add the volumes together. For isolated pads, enter one pad's dimensions, note the volume, and multiply by the number of pads. Complex shapes benefit from a structural drawing takeoff rather than this tool alone.

Cautions

•Rebar weight (90 kg/m³) is a quick estimate without structural drawings. For permitted buildings, always follow the rebar schedule from your structural engineer.
•Truck count is for reference. Confirm minimum order volume (usually 3 m³), delivery time limits, and pour sequencing with your ready-mix supplier.
•Waste factor varies by site conditions. The default 5% suits straightforward sites; complex or uneven sites may need 10%.
•This calculator does not assess structural adequacy. Any building requiring a permit must be reviewed by a licensed structural engineer.
•Concrete mix design variables (water-cement ratio, slump, admixtures) are outside the scope of this tool.

Last reviewed: 2026-06-17