Concrete, Mulch & Topsoil Calculator
Three materials, one tool. Get exact bag counts for concrete, loose volume for mulch, or settled volume for topsoil — plus a cost estimate and shopping list. Switch between cubic metres and cubic yards instantly.
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Concrete & mulch calculator FAQ
Patios, walkways, and shed bases: 10 cm (4 in). Driveways and garage floors: 12–15 cm (5–6 in) with reinforcement. Footings for retaining walls: 30 cm minimum. Always check local building codes — frost-line depth varies by region and may require deeper footings.
For projects under ~1 m³ (about 60 bags of 25 kg), bagged concrete mixed on-site is usually cheaper once you factor in delivery fees. Above 2 m³, ready-mix delivered by truck becomes more economical and saves enormous physical effort. For anything over 3 m³, always use ready-mix.
5–7 cm (2–3 in) is the sweet spot — thick enough to suppress weeds and retain moisture, thin enough to let water and air reach roots. Going over 10 cm (4 in) can suffocate plant roots and promote fungal disease. Refresh annually by adding 2–3 cm rather than piling it on.
Loose topsoil contains air pockets that compress under their own weight and rainfall. Expect 15–20% settling in the first season. If you need a finished grade of 10 cm, order 12 cm of loose soil. Water thoroughly after spreading to accelerate settling before planting.