Concrete Footing Calculator
Estimate concrete requirements for construction footings with the Concrete Footing Calculator. Calculate total volume based on footing dimensions, quantity, and waste allowance. Useful for deck footings, foundation work, fence posts, and structural supports.
This calculator provides estimates only. Actual concrete requirements may vary based on site conditions, excavation accuracy, and placement methods. Contact a licensed contractor or engineer for project-specific calculations.
How This Calculator Works
- Step 1: Select your footing shape (rectangular or circular) and enter the dimensions.
- Step 2: Enter the depth, quantity of footings, and waste factor percentage.
- Step 3: The calculator computes volume using geometric formulas and applies unit conversion.
- Step 4: Review your estimated concrete volume in cubic yards or cubic meters.
How Concrete Footing Volume Is Calculated
The calculator determines concrete volume by applying standard geometric formulas based on footing shape, then converting the result to practical ordering units.
Rectangular Footing Formula
V = Length × Width × Depth
Circular Footing Formula
V = π × (Diameter ÷ 2)² × Depth
Total Volume with Waste
Vtotal = (V × Quantity) × (1 + Waste Factor ÷ 100)
Where:
- V = Volume in cubic units
- π ≈ 3.14159
- Waste Factor accounts for spillage and over-excavation
For Imperial units, the result in cubic feet is divided by 27 to convert to cubic yards (the standard concrete ordering unit). Metric calculations remain in cubic meters.
Conversion Note
1 cubic yard = 27 cubic feet. Concrete is typically ordered in quarter-yard increments (0.25 yd³).
Estimates are based on ideal geometric shapes. Actual volume may vary with site conditions and formwork tolerances.
What Your Concrete Volume Means
The calculated volume represents the amount of concrete you may consider ordering for your footing project. Understanding this number helps with budgeting, scheduling deliveries, and avoiding shortages or excess material.
| Project Type | Typical Volume Range | Ordering Guidance |
|---|---|---|
| Deck Posts (4-6 footings) | 0.5 - 2.0 yd³ | Consider bagged mix or mini-mix delivery |
| Fence Posts (10-20 footings) | 0.3 - 1.5 yd³ | Bagged mix often most practical |
| Shed Foundation | 1.0 - 3.0 yd³ | Ready-mix delivery recommended |
| House Foundation | 10+ yd³ | Ready-mix truck delivery required |
For Small Projects (under 1 cubic yard): Bagged concrete mix from hardware stores may be convenient. Each 60-lb bag yields approximately 0.45 cubic feet (0.017 yd³).
For Medium Projects (1-6 cubic yards): Consider mini-mix trucks or short-load deliveries. Some suppliers have minimum order requirements or short-load fees.
For Large Projects (over 6 cubic yards): Standard ready-mix trucks typically carry 10-14 cubic yards. Coordinate delivery timing and ensure adequate access for the truck.
Important Note
Always round up your order slightly and confirm availability with your supplier. Concrete has a limited working time (typically 90 minutes) from batch to placement.
Consider ordering 5-10% extra concrete as a buffer. Running short during a pour may result in cold joints or additional delivery charges.
References
- American Concrete Institute (ACI) - Residential Concrete Guidelines
- National Ready Mixed Concrete Association (NRMCA) - Concrete in Practice
- International Code Council - Residential Building Code Requirements
- Portland Cement Association - Design and Control of Concrete Mixtures
Calculation logic verified using publicly available standards.
View our Accuracy & Reliability Framework →