VolunaroMulch calculator
How the calculation works
- Area: we add up every shape you enter and subtract the ones marked as cut-outs, such as a tree or a path through the bed.
- Volume: area × depth gives the net volume of mulch. We then add the margin for settling and uneven beds. One cubic yard covers 108 sq ft at 3 in deep.
- Bags: volume divided by the volume of the bag size you enter (2 cu ft by default), rounded up. Bulk mulch is sold by the cubic yard, so compare both.
Worked example
A 12 × 10 ft garden bed mulched 3 in deep, with the default 5 % margin and 2 cu ft bags.
- Area
- 120.0 sq ft
- Mulch to order
- 1.17 cu yd
- Bags
- 16
Default values and sources
| Value | Default | Type | Sources |
|---|---|---|---|
| Settling and waste margin for mulch | 5 % | Our default (editable) | — |
| Typical retail bag of mulch | 2 cu ft | Our default (editable) | — |
Limitations
- Mulch settles and breaks down: the margin covers settling and uneven beds, and shredded or fine mulch may need a larger one. Keep it clear of plant stems and tree trunks.
- Bag sizes vary between stores and brands: use the volume printed on your bag. Bulk delivery is priced per cubic yard.
Results are estimates for planning and ordering, not professional, engineering or legal advice. Confirm quantities, sizes and local building requirements with your supplier or contractor before you buy or build.