Foundation Concrete Calculator: Footings, Walls and Slab

Foundation Concrete Calculator

Combine continuous footings, foundation walls, a slab and round piers in one concrete estimate.

Measurement system

Extra concrete (%)Adds a stated allowance after all components are combined.

Continuous footings

Include continuous footings

Total footing length (ft)

Footing width (in)

Footing depth (in)

Foundation walls

Include poured walls or stem walls

Total wall length (ft)

Wall thickness (in)

Wall height (in)

Slab inside the foundation

Include a rectangular slab

Slab length (ft)

Slab width (ft)

Slab thickness (in)

Round piers or piles

Include identical round piers

Number of piers

Pier diameter (in)

Pier depth (in)

Bags, ready-mix and cost

Concrete yield per bag (ft³)Use the mixed yield printed on the product.

Price per bag

Ready-mix price per yd³

Truck capacity (yd³)

Concrete including allowance—

—Geometric concrete volume

—Whole bags

—Bag purchase cost

—Ready-mix material cost

—Full-capacity truck equivalents

—Bag yield above planned volume

Component breakdown

Component	Volume before allowance	Share of foundation

How the foundation estimate works

Measure each concrete component without counting overlaps twice. Enter the total centerline length of continuous footings and walls. The calculator combines enabled components, applies one allowance to the total and then rounds bags upward.

Formulas

Continuous footing volume = total length × width × depth. Wall volume = total length × thickness × height. Slab volume = length × width × thickness. Round pier volume = number of piers × π × diameter² ÷ 4 × depth. Planned concrete = combined geometric volume × (1 + allowance ÷ 100).

Checked example

A 10 × 12 ft shed foundation with 44 ft of 12 × 8 in continuous footing, 44 ft of 8 × 24 in stem wall and a 4 in slab contains 128 ft³ before allowance. With 10% extra, plan 140.8 ft³, equal to about 5.215 yd³ or 3.987 m³. Bags yielding 0.60 ft³ require 235 whole bags.

Important limits

This estimates quantity only. It does not design footing width, wall thickness, pier size, concrete strength, reinforcement, drainage, frost protection or bearing capacity.
Do not subtract overlapping volumes automatically. If a slab, wall and footing geometrically overlap, enter net component dimensions or schedule each placement separately.
Excavations and forms are imperfect. Choose an allowance appropriate to measurement uncertainty and placement conditions.
Bag yield and ready-mix prices are editable examples. Confirm the exact product yield, supplier minimums, delivery, short-load fees, taxes and truck access.
Use structural drawings, local code and a qualified professional for design decisions.

Related calculators

Use the Concrete Calculator for a single general slab, the Sonotube Concrete Calculator for form tubes and enlarged bases, or the Rebar Calculator for a user-specified reinforcement layout.

Need a wall-only takeoff? Use the Concrete Wall Calculator for openings, different wall sections, form-contact area, weight and purchasing quantities.

Using insulated concrete forms? Use the ICF Concrete Calculator to estimate net wall area, straight form units and concrete from the selected system’s published fill data.