Calculated result
1.25yd³
Ready-mix order
Formula
CONC-FOOT-001Footing length × width × depth × quantity ÷ 27 × (1 + waste)
26.67 ft³
Net footing volume
0.99 yd³
Net volume
0.13 loads
10 yd³ truck-load equivalent
Concrete calculator
Concrete footing calculator
Continuous footing volume, ready-mix quantity, and whole-bag equivalent.
By Feroz Sheikh · Formula CONC-FOOT-001 v1.1.0 · Tested formula
Formula
CONC-FOOT-001v1.1.0Project inputs
Enter your measurements. Switching units converts the same project, including coverage and unit rates. Package yields keep the unit printed beside each field.
Refine measurements and rates at any time. Your current values are included in the material-list PDF.
Planning estimate, not engineering advice. Confirm site measurements and product specifications. Calculation limits.
Bag table · waste in
Counts round up. A cubic yard is 45 of 80 lb, 60 of 60 lb, 72 of 50 lb, 90 of 40 lb.
| Bag | Count |
|---|---|
| 60 lb | 66 |
| 80 lb | 49 |
This calculator returns ready-mix volume for a continuous strip footing from centerline length, width and depth. Formula CONC-FOOT-001 v1.1.0. Waste and quarter-yard rounding stay visible. Carry the line into an estimate and a quote letter. It does not size a footing or set soil bearing.
- Measure the continuous footing length along its centerline.
- Enter the actual width and concrete depth required by the approved design.
- Use the rounded result as a starting point for a ready-mix supplier quote.
Size chart
Footing run chart (2 ft × 8 in, 10% waste)
Centerline length. Width and depth come from the approved design — this table does not size a footing or set soil bearing.
| Centerline | Ready-mix order | 40 lb | 60 lb | 80 lb |
|---|---|---|---|---|
| 20 ft | 1.25 yd³ | — | 66 | 49 |
| 40 ft | 2.25 yd³ | — | 131 | 98 |
| 60 ft | 3.5 yd³ | — | 196 | 147 |
| 80 ft | 4.5 yd³ | — | 261 | 196 |
| 100 ft | 5.5 yd³ | — | 326 | 245 |
Metric example — 12 m strip. A 12 m centerline at 600 mm × 100 mm with 10% waste orders 0.8 m³. Width and depth still come from the approved design.
Bags vs bulk. A continuous strip is usually a truck. Bags belong on isolated pads and post holes, not a 40 ft footing.
- Volume method. A continuous strip is length × width × depth. Centerline length is the measurement basis on this page. Concrete Network — volume calculation guidance
- ASTM C94/C94M. Ready-mix is ordered by volume. This tool does not size a footing or set soil bearing. ASTM C94/C94M — ready-mixed concrete
- ACI 332. Residential concrete design is a separate document. Width and depth come from the approved design, not from this takeoff. ACI — residential concrete
Add your project costs
Enter supplier prices and any labour, equipment or delivery costs. Pick a currency — badges, inputs, and totals follow.
Enter your supplier’s ready-mix concrete rate in the selected unit. Add delivery, pumping, short-load fees and placing labour as separate project costs. For GCC projects, select QAR, AED, SAR, KWD, OMR or BHD and enter local supplier rates.
How this calculator works
A transparent concrete footing takeoff.
Feroz SheikhWritten by Feroz Sheikh · founder
Use finished continuous-footing dimensions to establish concrete volume, then apply a visible waste allowance before supplier purchase rounding.
The footing takeoff follows the centerline of a continuous strip, then shows waste and purchase rounding instead of a single buried volume. Formula ID stays on the sheet so a later estimator can change width without guessing what was assumed.
Worked example. Example: a 20 ft long footing, 2 ft wide and 8 in deep contains about 1.0 yd³ of concrete before a 10% allowance. The published formula rounds the order to a quarter-yard purchase increment.
See the example inputs and calculated result
This separate example uses the calculator's starting values in imperial units. It stays unchanged when you edit the tool above. Example rates, yields and dimensions are assumptions, not recommendations for your project.
| Input | Example value |
|---|---|
| Footing length | 20 ft |
| Footing width | 2 ft |
| Footing depth | 8 in |
| Number of footings | 1 count |
| Waste factor | 10 % |
Example result: Ready-mix order — 1.25 yd³.
Footing length × width × depth × quantity ÷ 27 × (1 + waste)
Use the labelled units above when reproducing this example. To work in metric, switch the calculator to Metric; applicable measurements are converted, while product-specific units remain labelled.
- 1. Measure the continuous footing length along its centerline.
- 2. Enter the actual width and concrete depth required by the approved design.
- 3. Use the rounded result as a starting point for a ready-mix supplier quote.
Field notes that change the number
- Length is the centerline, not the outside of the excavation.
- Width and depth come from the approved design. This tool does not size a footing or set soil bearing.
- Step footings and isolated pads are separate takeoffs, not one averaged strip.
Common mistakes
- Using wall length when the footing returns past the wall.
- Hiding rebar and formwork inside the concrete yards.
- Ignoring over-excavation that will be filled with extra concrete if the trench is sloppy.
Metric footings are millimetres of width and depth, metres of run. GCC plants will still round the order — typically 0.1 m³.
Need the broader workflow? Read the concrete planning guide.
How-to: How to plan a slab rebar grid
Questions
Questions about concrete footing
Does this determine footing size?
No. Footing dimensions, reinforcement, soil bearing and local requirements must be set by the responsible professional.
Why is waste added?
Excavation variation, placement loss and supplier ordering increments can make a net-volume-only order too small.
How much concrete for a 40 ft footing?
A 40 ft centerline at 2 ft × 8 in with 10% waste orders 2.25 yd³. Width and depth come from the approved design — this tool does not size a footing.
Is a continuous footing a bag job?
Usually a truck. Bags belong on isolated pads and post holes, not a 40 ft strip.
What is the formula ID?
This concrete footing calculator publishes formula CONC-FOOT-001, version 1.1.0. The ID stays on the result and on the estimate line.