TryBuildCalcFooting Concrete Calculator in Feet (Isolated, Strip & Circular — Volume, Cement, Sand & Aggregate)
Calculate footing concrete volume and materials.
Calculate footing concrete when dimensions are entered in feet and inches. Adjust footing type, dimensions, count, mix ratio, and wastage for your foundation estimate.
🕒 Last updated: August 4, 2026
Inputs
ℹ️Isolated/Pad supports a single column. Strip/Continuous runs under a wall or a closely spaced row of columns — same formula as Isolated, just usually a much longer run. Circular/Pier is a round base, common under a single steel column or post.
ℹ️The plan length of a single footing.
Cost
Showing results for 4 footings
Concrete Volume
3.398 m³ / 120.0 cft
(0.850 m³ / 30.0 cft per footing)
Total Wet Volume: 3.398 m³ / 120.0 cft
Dry Volume: 5.233 m³ / 184.8 cft
Sand: 1.427 m³ / 50.4 cft
Aggregate: 2.854 m³ / 100.8 cft
(Per footing: Sand 0.357 m³ / 12.6 cft, Aggregate 0.714 m³ / 25.2 cft)
Cement Required
(Including 5% Wastage)
29 bags
(8 bags per footing)
Extra (Wastage): 1.37 bags
Approximate results for planning only. Verify with a professional.
Looking for the verification checklist, reference tables, tips, or common mistakes?See the complete Concrete Footing Calculator.
Footing concrete from feet and inches
This page is useful for field dimensions entered in feet and inches.
The calculator is pre-filled for this footing use case. Edit any input and the worked example updates from the active values.
- Footing size: 6 ft x 4 ft.
- Thickness: 15 in.
- Converts to cubic meters.
How does the concrete footing calculator work?
Wet volume depends on the footing shape — Isolated and Strip share the same rectangular formula, while Circular uses the circle area instead. Every shape then follows the same dry-volume, mix-ratio, and wastage steps.
Step 1 — Isolated / Strip (Rectangular)
A Strip footing uses the exact same formula — its "Length" is just a wall run instead of a small pad.
Step 2 — Circular / Pier
Enter the diameter, not the radius — the formula already halves it.
Step 3 — Convert to Dry Volume
The 1.54 factor accounts for voids in aggregates, sand bulking, and material loss during mixing.
Step 4 — Split by Mix Ratio
Step 5 — Convert Cement Volume to Bags
Step 6 — Add Wastage
Step 7 — Cost (Optional)
All three quantities are priced at their wastage-adjusted amount — the quantity you'd actually order, not the theoretical minimum before wastage. Sand and aggregate prices can be entered per m³ or per cft — whichever unit you enter is converted to match the volume automatically.
Worked Example
This example uses the active inputs above and follows the same steps as the Formula section.
Input Values Used
| Input | Value |
|---|---|
| Footing Type | Isolated / Pad Footing |
| Length | 6 ft (1.829 m) |
| Width | 4 ft (1.219 m) |
| Thickness | 15 in (0.381 m) |
| Count | 4 |
| Concrete Mix | M20 (1:1.5:3) |
| Wastage | 5% |
Step 1 — Wet Volume
| Calculation | Substitution | Result |
|---|---|---|
| L × W × T × Count | 1.829 × 1.219 × 0.381 × 4 | 3.398 m³ / 120.0 cft |
Step 2 — Dry Volume
| Calculation | Substitution | Result |
|---|---|---|
| Dry Volume = Wet Volume × 1.54 | 3.398 × 1.54 | 5.233 m³ / 184.8 cft |
Step 3 — Materials & Cement Bags
| Material | Share of Mix (1:1.5:3) | Result |
|---|---|---|
| Sand | 1.5 / 5.5 | 1.427 m³ / 50.4 cft |
| Aggregate | 3 / 5.5 | 2.854 m³ / 100.8 cft |
| Cement Bags (with 5% wastage) | 1 / 5.5 | 29 bags |
Therefore, this isolated / pad footing needs approximately 3.398 m³ / 120.0 cft of concrete, requiring 29 cement bags, 1.427 m³ / 50.4 cft sand, and 2.854 m³ / 100.8 cft aggregate (including 5% wastage on cement).
Cross-check against the Footing Type & Mix Reference table in the complete Concrete Footing Calculator.