Mulch and soil calculator
Estimate mulch or soil for beds and whole bags from your bag size; 4 × 3 m at 0.1 m deep with 10 % extra is 1.32 m³.
- Runs in your browser
- No upload
- Instant result
Quantity estimate only. This does not approve structural safety, load capacity, drainage, fire resistance or building-code compliance. Verify the design and local requirements with a qualified professional. Purchase quantities round up to whole packs.
Assumptions & formula
Formula and assumptions
w = Waste allowance/100; V=(ΣLW−Σab)h(1+w); N=ceil(V×1000/L); 0≤w≤25%
The prefilled values are editable examples, not product specifications. Enter your supplier’s yield, density, coverage and packaging values, and add an allowance for overlaps, compaction and cuts where needed.
Purchase counts use the exact entered decimals and unit factors, without a rounding tolerance that could discard a real remainder. π and irrational square roots use enclosing bounds; ambiguous counts produce an error. Counts must be safe integers.
Results
Enter values and press Calculate to see the result here.
How to use this calculator
- Set inputs and units
Enter rectangular beds, excluded areas, the layer depth and the liters per bag, and select one unit for the dimensions.
- Calculate
Check this worked example: (4×3+2×2−1×1) m² ×0.1 m; waste=0%; bag=40 L → 1.5 m³=1500 L →38 bags
- Results
Bags to purchase are rounded up. For settling or compaction, add your own allowance; there is no hidden automatic factor.
Questions and limits
Can I enter depth in centimeters while length is meters?
Not without converting. The length unit you select applies to all geometric lengths, including depth.
Which input errors should I correct?
Bag liters must be positive. Subtract only rectangles that are really uncovered, and keep the remaining area positive.
What does this calculation leave out?
Volume and purchasing arithmetic. It is not about soil composition, whether plants will do well, or a prescribed horticultural depth.