Concrete Footing Calculator – Strip, Pad & Piers

For a uniform strip footing, multiply its net length by its width and concrete depth. Convert all values into compatible units. Where the strip follows several walls, take special care at corners and intersections: overlapping rectangles cannot be counted twice. Add a separate strip section if width or depth changes. The output is a volume estimate, not confirmation that the footing dimensions are adequate.

Choose a rectangular section and enter one pad length, width and depth. Set Quantity to the number of identical pads. If some pads have different sizes, add them as separate named sections. The calculator multiplies each pad volume by its quantity and sums the sections. It also reports allowance and supplier rounding separately for purchasing.

Worked example: Four identical pads each measuring 1.2 m long × 1.2 m wide × 0.4 m deep need 4 × (1.2 × 1.2 × 0.4) = 2.304 m³ net. At 5% allowance the required quantity is 2.4192 m³. Confirm the dimensions against approved drawings; a footing calculator cannot decide what size is structurally sufficient.

Yes. Choose the round-cylinder shape and enter the actual concrete-filled diameter and height/depth. The formula is π × (diameter/2)² × depth. Use Quantity for identical piers. If the hole is irregular, nominal auger diameter may not match excavated volume, so measure or justify any allowance carefully.

No. Depth and width are structural design decisions influenced by loads, soil bearing characteristics, settlement, frost conditions, local regulations and the selected foundation system. Use approved drawings or advice from a competent engineer. This calculator only estimates concrete volume for the dimensions supplied.

Break the plan into segments that do not overlap. For two intersecting rectangular strips, calculate one continuous strip first, then measure the second strip excluding the common intersection. Alternatively deduct a correctly dimensioned intersection if you calculated both full runs. Review the project summary to check additions and deductions before ordering.

An excavated trench can be wider or deeper than the design size because of overbreak, loose soil or irregular excavation. The correct quantity depends on the actual hole measurements and your project tolerances. Use the editable allowance only where supported by site conditions; do not replace measurement of a known large overbreak with an arbitrary percentage.

Yes. Add one named section per geometry group: rectangular pad footings, long strip sections, or round piers. Set quantity for repeated identical pours. The completed project total gives the net poured concrete before allowance, followed by order quantities and purchasing alternatives. Incomplete sections must be corrected or removed before the report is considered valid.

No. It cannot determine reinforcement, bearing capacity, embedment, uplift, geotechnical requirements, minimum code dimensions or structural adequacy. These are safety-critical decisions that require approved design information and professional assessment. Treat the output only as a material-quantity takeoff for a foundation already designed.