Estimate concrete for strip and pad foundation footings.
Total volume: 0.81 m³ (28.6 ft³)
Volume + waste: 0.89 m³
Cement: 167 kg
Sand: 371 kg
Gravel: 778 kg
Bag count (including waste):
Footing size and reinforcement come from the engineer's drawing and local building regulations — this calculator estimates the materials to fill the trench, not the structural design.
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Subject to Building Regulations and ground conditions.
Bar size, cage spacing, and cover come from the structural drawing. This calculator estimates concrete only.
This footing calculator estimates the concrete needed for strip and pad foundations. It is one of our concrete calculators, focused on the footing case where dimensions normally come from a structural drawing rather than a rule of thumb.
A strip footing is a continuous strip of concrete that runs beneath a load-bearing wall and spreads the wall's line load to the ground. Domestic extensions, garden walls, and traditional houses sit on strip footings.
A pad footing is a single rectangular or square block of concrete beneath a column, post, or pier. Steel-frame buildings, timber decks, pergolas, and garage portal frames sit on pad footings.
The volume math is the same for both — length × width × depth — but pad footings are usually multiplied across several identical pads, and strip footings are normally a single continuous run (or several runs that get added together).
The figures below are illustrative and subject to building regulations, soil bearing capacity, frost depth, and load — not a substitute for the project's footing schedule.
| Footing | Width (UK) | Depth (UK) | Width (US) | Depth (US) |
|---|---|---|---|---|
| Single-storey extension strip | 450 mm | 200–300 mm | 16–18 in | 8–10 in |
| Two-storey strip | 600 mm | 300 mm | 20–24 in | 10–12 in |
| Light pad (deck post) | 600 mm | 300–450 mm | 24 in | 12–18 in |
| Garage / portal column pad | 900 mm | 450 mm | 36 in | 18 in |
In the UK, the bottom of the footing is normally at least 750 mm below finished ground level for frost protection. In the US, the controlling number is the local frost line — common values are 12 in in the south and 48 in or more in northern states. The project drawing wins over any of these defaults.
Strip footing volume (m³) = length × width × depth
A 6 m strip × 450 mm wide × 300 mm deep is 6 × 0.45 × 0.3 = 0.81 m³. For an L-shaped footing, split into two rectangles and sum.
Pad footing volume (m³) = length × width × depth × number of pads
Four 600 × 600 × 300 mm pads work out to 4 × 0.6 × 0.6 × 0.3 = 0.43 m³. Identical pads share dimensions; if pads differ, run the calculator once per size and add the totals.
1. Domestic strip footing — 6 m × 450 mm × 300 mm
2. Four pad footings — 600 × 600 × 300 mm each
3. Heavy two-storey strip — 10 m × 600 mm × 450 mm
Reinforcement is out of scope for this calculator. As a rough orientation: many domestic strip footings on competent ground are placed as plain (unreinforced) concrete. Footings on poor or variable ground, footings near trees, and pad footings carrying significant moment normally need a steel cage. Bar size, spacing, cover, and lap length come from the structural drawing.
A strip footing is a long, narrow concrete strip that runs under a continuous wall and spreads its load to the ground. A pad footing is a single square or rectangular block beneath a column, post, or pier. Strip footings carry distributed line loads; pad footings carry point loads.
Strip footing volume = length × width × depth. A 6 m strip × 450 mm wide × 300 mm deep gives 6 × 0.45 × 0.3 = 0.81 m³. For an L-shaped or stepped strip, split into rectangles and add the volumes.
Pad footing volume = length × width × depth, then multiply by the number of pads. Four 600 × 600 × 300 mm pads work out to 4 × 0.6 × 0.6 × 0.3 = 0.43 m³.
In the UK, traditional domestic strip footings are commonly 450–600 mm wide and 200–300 mm deep, sitting at least 750 mm below finished ground level for frost protection. In the US, 16–24 in wide and 8–12 in deep is typical, with the bottom of the footing below the local frost line. Both are subject to building regulations and ground conditions.
No — it estimates the concrete materials for the dimensions you enter. Footing dimensions and reinforcement come from the engineer's drawing or local building regulations, which take into account loads, soil bearing capacity, frost depth, and any nearby trees or services.
A 1:2:4 foundation mix is the common reference point for general footing work. For heavier-load or structural footings, a 1:1.5:3 stronger mix is typical. Ready-mix suppliers in the UK quote by strength class (e.g. GEN1, ST2, ST4, RC25/30) — match the spec on the drawing.
Plain (unreinforced) concrete is acceptable for many domestic strip footings on good ground. Pad footings under columns, footings on poor or variable ground, and any footing carrying significant moment normally need a steel reinforcement cage. Bar size, spacing, and cover come from the structural drawing — out of scope for this calculator.
Add 10% for regular strip footings on well-prepared trenches. Add 15% or more for irregular trenches, over-excavated sections, or where the footing follows a stepped contour — trench bottoms are rarely as flat as the drawing suggests.
Up to the hub: Concrete Calculator. Sideways: Concrete Slab Calculator and Concrete Post Hole Calculator. Supporting converters: Volume, Length, and Weight.