Concrete Calculator

Volume = L × W × D. Add 10% waste — running short mid-pour is the expensive mistake.

Result

Concrete needed1.32 m³
25kg bags113
Ready-mix cost (~£120/m³)£158.40
Bag cost (~£6.50/25kg)£734.50
Weight3.17 tonnes

Concrete Calculator — FAQs

How thick should a slab be?

100mm for paths/patios, 125–150mm for driveways with vehicles, 75mm minimum for shed bases. Thickness matters more than length or width errors.

Bags or ready-mix?

Over ~1m³, ready-mix delivered is cheaper and less backbreaking. Bags make sense under 0.5m³ or awkward access.

Do I need reinforcement?

Mesh or rebar for anything over 100mm thick or vehicle-bearing — concrete is strong in compression, weak in tension.

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