Concrete Calculator
Free concrete calculator. Estimate concrete volume in cubic feet, yards, and meters and count the 40/60/80 lb pre-mixed bags needed for slabs, footings, columns, and post holes. Includes waste factor and cost. 100% client-side.
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What is Concrete Calculator?
The Concrete Calculator is a free, browser-based tool that estimates how much concrete you need for a pour. Choose from four common shapes — slab, footing, column (sonotube), or post hole — enter the dimensions in imperial or metric units, and it instantly computes the volume in cubic feet, cubic yards, and cubic meters. It then converts the volume into the number of 40 lb, 60 lb, or 80 lb pre-mixed bags required, with an adjustable waste factor and an optional cost-per-bag estimate. All math runs 100% client-side — no sign-up, no data uploads.
Key Benefits
- Four shapes — slab, footing, column, and post hole — cover most DIY and contractor pours
- Imperial (ft/in) and metric (m/cm) unit switching without re-entering dimensions
- Volume shown in ft³, yd³, and m³ at once so you can order from any supplier
- Bag count for 40 lb, 60 lb, or 80 lb bags with exact manufacturer yields
- Adjustable waste factor (default 10%) rounds up so you never run short mid-pour
- 100% client-side and offline-capable — your project data stays private
Common Use Cases
- •Homeowners pouring a patio, shed pad, or driveway slab
- •Building a deck or fence and need concrete for sonotube piers and post holes
- •Contractors estimating bags for small footings, steps, and retaining walls
- •DIYers comparing bagged concrete cost against a ready-mix delivery
- •Anyone ordering from a supplier that quotes in cubic yards or cubic meters
How to Use the Concrete Calculator
- Pick a shape: Choose Slab for a flat pour, Footing for a trench pour, Column for a vertical sonotube, or Post Hole for a round hole.
- Choose units: Switch to Imperial (feet and inches) or Metric (meters and centimeters) depending on how you measured the area.
- Enter dimensions: Type the length, width, and depth for slabs and footings, or the diameter and height for columns and holes. Add a waste percentage (default 10%) and an optional cost per bag.
- Read the results: See the volume in ft³, yd³, and m³ plus the exact number of 40/60/80 lb bags (rounded up). Copy the summary or add a price for a total cost estimate.
Key Features
- Four shapes: slab, footing, column (sonotube), and post hole
- Switch between imperial (ft/in) and metric (m/cm) units instantly
- Shows volume in cubic feet, cubic yards, and cubic meters together
- Counts 40 lb, 60 lb, or 80 lb pre-mixed bags with exact yields
- Adjustable waste factor (default 10%) rounds bags up so you never run short
- Optional cost-per-bag gives a total project cost estimate