RavenSharp logo
RavenSharp Tools Part of the Ascension Digital Group
Donate Here
🏗️ Lifestyle & Dates

Concrete Calculator

Calculate bags and m3 needed for slabs, footings and columns — with wastage.

Concrete for DIY Projects

Whether you are pouring a slab, setting posts, or building footings, getting your concrete quantity right saves money and extra trips to the hardware store. Always add 10% for wastage on standard jobs.

Bagged vs Premix

  • Bagged 25kg: Good for small jobs under 0.5m3. Mix yourself with a mixer or by hand.
  • Premix truck: Best for anything over 1m3. Usually sold in 0.2m3 minimum loads.

Standard Slab Thicknesses

  • Pathways: 75-100mm
  • Driveways: 100-125mm
  • Shed slabs: 100mm reinforced
  • House slabs: 85-110mm plus engineer spec

Tips

  • Always dampen the ground before pouring
  • Cure for at least 7 days before loading
  • Order 10-15% extra for uneven or rocky ground

Concrete Calculator

Calculate volume and bags for any concrete job.

Help keep these free tools coming

These tools are free to use. If they’ve helped you, a small donation helps keep new calculators, date tools, improvements, and updates coming.

Donate Here