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Foundation Concrete Coverage Calculator

Calculate plan area, uniform slab volume, thickened-edge volume, base concrete, waste allowance, order volume, truckloads, and coverage comparison.

Foundation length (m)Foundation width (m)Slab thickness (m)Thickened-edge length (m)Additional edge cross-section (m2)Concrete waste allowance (%)Ready-mix truck capacity (m3)Entered area comparison (m2)

Foundation plan area-

Uniform slab volume-

Additional thickened-edge volume-

Base concrete volume-

Entered waste allowance-

Concrete order volume-

Whole truckload reference-

Plan area per ordered cubic metre-

Plan area minus entered comparison-

Decision view

Foundation plan, section, and concrete fill

Foundation plan, section, and concrete fillPlan area, slab thickness, thickened-edge geometry, waste, and delivery capacity remain visually distinct.

Exact scenario comparisonSlab thickness (m) changes while all other entered assumptions remain constant.

Slab thickness (m)	Foundation plan area	Uniform slab volume	Additional thickened-edge volume	Base concrete volume	Entered waste allowance	Concrete order volume	Whole truckload reference	Plan area per ordered cubic metre	Plan area minus entered comparison

How to use Foundation Concrete Coverage Calculator

Enter foundation length, width, and slab thickness.
Enter thickened-edge length and additional cross-section.
Enter waste percentage and truck capacity.
Review the plan, section, and quantity decomposition.

Calculator guide

Understanding Foundation Concrete Coverage Calculator

Foundation concrete quantity combines plan area, slab thickness, and additional thickened-edge cross-section. Waste and truck capacity should be added only after geometric volume is reconciled.

Geometry first Area and sections stay explicit.

Edge adds volume Extra cross-section times length.

Waste once Applied to combined base volume.

Trucks round up Capacity is whole-load reference.

Calculation method

How the calculation works

Calculate foundation coverage from separate slab and thickened-edge geometry, then add the entered waste allowance and convert the concrete order to whole-truck capacity. Multiply plan dimensions for area, multiply area by slab thickness, add edge length times extra cross-section, then add waste and round truck capacity upward.

Detailed calculation process

Reconcile foundation geometry into an order quantity

The default foundation is 18 m by 10 m with a 0.15 m slab, 56 m of thickened edge adding 0.08 m² per metre, 7% waste, and 8 m³ trucks.

General formula: A = LWV_s = AhV_e = l_ea_eV_b = V_s+V_eV_w = V_bwV_o = V_b+V_wN = ceil(V_o/C)q = A/V_o Plan area becomes slab volume through thickness. The edge uses its own cross-sectional geometry, waste applies to the combined base volume, and truckloads round upward.

What each symbol means

L, W, A Foundation length, width (m), and plan area (m²).

h, V_s Slab thickness (m) and uniform slab volume (m³).

l_e, a_e, V_e Edge length (m), extra cross-section (m²), and edge volume (m³).

V_b Base geometric concrete volume (m³).

w, V_w Waste share and waste volume (m³).

V_o, C, N Order volume, truck capacity, and whole truckloads.

q Plan area per ordered cubic metre (m²/m³).

Worked substitution with the default inputs

1. Calculate plan area A = 18×10 = 180 m²comparison gap = 180-200 = -20 m² The entered rectangular footprint is 20 m² below the comparison area.

2. Calculate slab volume V_s = 180×0.15 = 27 m³ The uniform slab is modeled at one thickness.

3. Calculate thickened-edge volume V_e = 56×0.08 = 4.48 m³V_b = 27+4.48 = 31.48 m³ Only the additional edge cross-section is added to the slab volume.

4. Add waste allowance V_w = 31.48×7% = 2.2036 m³V_o = 31.48+2.2036 = 33.6836 m³ Waste is applied once to total base geometry.

5. Convert to delivery capacity N = ceil(33.6836/8) = 5 truckloadsq = 180/33.6836 = 5.343 m²/m³ Whole-truck reference rounds upward and does not imply every truck must be full.

The default geometry requires 31.48 m³ before waste and 33.6836 m³ for ordering, equivalent to five 8 m³ truck-capacity references.

Construction geometry

See footprint, slab section, and truck fill together

A plan view shows dimensions, a section distinguishes uniform slab from thickened edge, and a fill gauge reconciles ordered volume against truck capacity.

Plan 18 m × 10 m footprint.

Slab Uniform 0.15 m depth.

Edge Additional section volume.

Delivery Whole truck references.

Worked situations

Practical examples

The footprint is 180 m².
The slab uses 27 m³ and thickened edge adds 4.48 m³.
Seven percent waste brings the order to 33.6836 m³.

Better inputs

Useful tips

Use only the edge area beyond the uniform slab section.
Confirm dimensions from structural drawings.
Coordinate partial-load and delivery constraints with the supplier.

Before relying on the result

Limitations and common mistakes

Beams, piers, steps, overbreak, pumping loss, reinforcement, subbase, excavation, and code design are excluded.
The footprint is rectangular.
Truckloads are capacity references, not a dispatch plan.

Reference

Key terms

Plan area: Horizontal foundation footprint.
Extra edge cross-section: Thickened area beyond the uniform slab.
Order volume: Base geometry plus entered waste.

Important note

Calculated from the entered measurements and stated coverage or quantity rules. Confirm field dimensions, waste, product requirements, structural conditions, and local codes before purchasing or building.

Frequently asked questions

Why add only extra edge area?

The uniform slab already includes the slab portion beneath the edge.

Why round truckloads upward?

A fractional requirement needs capacity from another truck reference.

Does five truckloads mean five full trucks?

No. It is order volume divided by entered capacity, rounded up.

Is reinforcement included?

No. This page calculates concrete volume only.