TryBuildCalcStrip Footing Calculator (Isolated, Strip & Circular — Volume, Cement, Sand & Aggregate)
Calculate footing concrete volume and materials.
Calculate concrete volume and materials for strip (continuous) footings under a wall or column row. 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 total length of the continuous wall/column run this footing supports.
Cost
Concrete Volume
2.700 m³ / 95.3 cft
Total Wet Volume: 2.700 m³ / 95.3 cft
Dry Volume: 4.158 m³ / 146.8 cft
Sand: 1.188 m³ / 42.0 cft
Aggregate: 2.376 m³ / 83.9 cft
Cement Required
(Including 5% Wastage)
18 bags
Extra (Wastage): 0.86 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.
15 m strip footing, 0.6 m wide x 300 mm thick
A strip (continuous) footing runs under a load-bearing wall or a closely spaced row of columns, so it uses the same Length x Width x Thickness formula as an isolated footing — just over a much longer run. For a 15 m run at 0.6 m wide and 300 mm thick, wet volume is 2.7 m³, dry volume 4.158 m³, needing about 18 cement bags (1:2:4 mix, 5% wastage), 1.188 m³ sand, and 2.376 m³ aggregate.
The calculator is pre-filled for this footing use case. Edit any input and the worked example updates from the active values.
- Default run: 15 m x 0.6 m wide, 300 mm thick.
- Same formula as Isolated — L x W x T.
- ~18 cement bags with 5% wastage (1:2:4 mix).
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 | Strip / Continuous Footing |
| Run Length | 15 m (15 m) |
| Width | 0.6 m (0.6 m) |
| Thickness | 300 mm (0.3 m) |
| Count | 1 |
| Concrete Mix | M15 (1:2:4) |
| Wastage | 5% |
Step 1 — Wet Volume
| Calculation | Substitution | Result |
|---|---|---|
| L × W × T × Count | 15 × 0.6 × 0.3 × 1 | 2.7 m³ / 95.3 cft |
Step 2 — Dry Volume
| Calculation | Substitution | Result |
|---|---|---|
| Dry Volume = Wet Volume × 1.54 | 2.7 × 1.54 | 4.158 m³ / 146.8 cft |
Step 3 — Materials & Cement Bags
| Material | Share of Mix (1:2:4) | Result |
|---|---|---|
| Sand | 2 / 7 | 1.188 m³ / 42.0 cft |
| Aggregate | 4 / 7 | 2.376 m³ / 83.9 cft |
| Cement Bags (with 5% wastage) | 1 / 7 | 18 bags |
Therefore, this strip / continuous footing needs approximately 2.7 m³ / 95.3 cft of concrete, requiring 18 cement bags, 1.188 m³ / 42.0 cft sand, and 2.376 m³ / 83.9 cft aggregate (including 5% wastage on cement).
Cross-check against the Footing Type & Mix Reference table in the complete Concrete Footing Calculator.