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Concrete Calculator

Measure rectangular, circular and annular concrete groups with depth ranges, counts and voids. Reconcile exact bag yields or ready-mix terms and save source-owned planning records.

Use this result well

Inputs that matter
Named rectangular/circular/annular groups, counts, depth endpoints, voids and exact purchase evidence
Output to expect
Source-owned quantity endpoints, optional real purchase multiples and complete original-unit JSON; no construction-status claims
How it works
Separates measured net volume, entered extras and exact supplier/product purchase arithmetic
  • Confirm source dimensions, non-overlapping exclusions and allowances; original units are retained and no contingency or product yield is universal.
  • Quantity is not design or completed work. Review current plans, product and supplier evidence; saving never confirms placement, inspection or approval.

Choose your path

Built around the job you need to finish

Measure repeated rectangular, circular and annular forms, reconcile depth/void endpoints and save only owned planning quantities.

DIY owner measuring forms

Measure actual geometry without inferring a footing design.

Choose shape and count, enter diameters or rectangle dimensions and depth endpoints; inspect each group.

Can reproduce net volume and distinguish additional allowance.

Estimator checking a supplier order

Retain exact product yield, original units and quote terms.

Switch display units, revise the product basis, correct cleared fields and export the record.

No universal bag yield or ready-mix increment is invented.

Deck or Fence coordinator

Save quantities without claiming construction is complete.

Open the intended Project, review source inputs, explicitly save, reload and compare owned fields.

Prior bag counts and construction observations remain unchanged.

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Reference & details

How it works

Independent measured form groups

Rectangles use length × width; circles use πD²/4; annular forms use π(D²−d²)/4. Circular inputs are diameters. Sum only non-overlapping groups of one compatible mix.

Net group = count × (cross-section × depth − extra void)

Separate geometry and planning extras

Depth endpoints express reviewed variation, not confidence intervals. Do not add the same variation again through the allowance. Each original number and unit survives display changes.

Planned endpoints = net endpoints × (1 + additional allowance/100) + reserve

Exact purchase and evidence ownership

Use documented bag yield from the exact product, or enter supplier ready-mix minimum and order increment. Quantity outputs use independent Project keys and never overwrite construction observations or another tool’s bags.

Bags = ceil(volume/yield); sale packs = ceil(max(0, bags−whole stock)/pack size)

Updated: August 2026

Example Scenarios

Illustrative 10×8ft at4in gives26.666667ft³ net; an entered10% allowance gives29.333333ft³. A reviewed0.6ft³ bag yield requires49 whole bags before stock and sale-pack rounding.

Record the measured diameter, depth range and identical count for one group. A different diameter belongs in another group; no deck height or post count is silently used as footing geometry.

Download the complete input/quantity record, then explicitly save its source-owned fields to the intended Deck or Fence Project. Existing observations, checklists and other tool quantities remain separate.

Common Mistakes to Avoid

Mixing diameters with radii or repeating overlapping volumes

Check the shape labels and deduct only distinct voids; thickened portions must not duplicate a slab volume already counted.

Treating a saved estimate as completed work

Keep planning quantities separate from construction observations, authority approvals and inspection records.

FAQ

Diameters. The calculator divides by two in the area formula. Annular mode subtracts a centered inner circular core; do not subtract that same core again as an extra void.

Yes, up to six non-overlapping groups sharing one compatible concrete mix and placement scope. Different products or separately procured scopes should have separate downloaded records.

No. The illustration is not a site recommendation. Choose and document it from the measured forms, tolerance range, placement plan and supplier discussion.

No. Only source-owned concrete planning fields are saved. Poured-footing observations, posts set, approvals, inspections and another tool’s concreteBags remain unchanged.

No. Use approved plans, exact product and supplier documentation, site conditions and qualified review. Quantity arithmetic does not establish structural suitability, safe placement or compliance.

About Concrete Calculator

Build a measured takeoff from up to six non-overlapping pour groups. Keep original units, depth endpoints, voids, extra allowance and supplier evidence traceable. Explicit Project Save records planning quantities only, never poured footings or installation approval.