Concrete Calculator
Calculate the exact volume of concrete needed for slabs, footings, columns, or steps. Convert to bags of ready-mix or cubic metres for ordering ready-mixed.
Concrete Mixing Guide
Bag Coverage
A 25kg bag of general-purpose concrete mix covers approximately 0.012 m³. A 40kg bag covers approximately 0.019 m³. Always add 10% for waste and overfill.
Ready-Mixed vs Bagged
For volumes over 0.5 m³, ready-mixed concrete is usually more cost-effective and gives more consistent results. For small garden projects under 0.3 m³, bagged mix is more practical.
Concrete Grades
C20 is standard for domestic slabs and garden paths. C25 for driveways. C30 for foundations. Post holes and fence post setting can use a lean mix: 1 part cement : 3 parts sharp sand : 6 parts aggregate.
Related products on Amazon
As an Amazon Associate we earn from qualifying purchases.