Loona Construction Calculators
Mulching beds, borders or a play area? Enter the area and the depth of mulch you want, and get the volume plus how many bags to buy — 40 or 50 litre bags in metric, 2 or 3 cubic-foot bags in imperial — or the bulk amount in cubic metres and cubic yards.
7.5 cm (3 in) is the standard recommendation for beds and borders — enough to suppress weeds and hold moisture without smothering plants. 5 cm is a minimum top-up depth; 10 cm suits new beds and trees.
A 50 litre bag at 7.5 cm deep covers about 0.67 m²; a 2 ft³ bag covers about 7.5 ft² at 3 in deep. Coverage halves if you double the depth — always calculate from volume, not from bag marketing claims.
Bags win for small areas and clean handling. Beyond roughly 2 m³ (about 40 fifty-litre bags), bulk bags or a loose tipped load are usually much cheaper per litre and mean far less plastic waste.
Volume = Length × Width × Depth
Bags = Volume × (1 + Waste %) ÷ Bag volume
Bag volumes: 50 litres = 0.05 m³, 40 litres = 0.04 m³, 2 ft³ = 0.0566 m³, 3 ft³ = 0.0850 m³. One cubic yard (27 ft³) covers about 9.7 m² at 7.5 cm (3 in) deep.
Yes — organic mulches settle and decompose, losing roughly a quarter of their depth in the first season. The 10% extra allowance covers initial settling; plan a light top-up each year.
Yes — the calculation is pure volume, so it works for bark, compost, topsoil, sand and play bark alike. Only the bag sizes on sale differ; pick the closest bag volume.
Yes — switch to Imperial for feet and inches, and 2 or 3 ft³ bags. The bulk result is shown in cubic yards alongside cubic metres.
Add this calculator to your own website or blog — it is completely free, needs no sign-up, and always shows the latest version. Copy the code below and paste it into your page where you want the calculator to appear. Keeping the small “Powered by Loona Automation” credit line under the embed helps keep this tool free — but you are free to style or remove it; the tool works either way.