Mulch Calculator

About this calculator

Mulch is sold and applied by volume, not area, so working out how much you need means multiplying the bed's length × width by the depth you want to spread it, then converting that volume into the units bags are sold in. A typical recommended depth for most garden beds is 2 to 4 inches (about 5 to 10 cm), enough to suppress weeds and retain soil moisture without smothering plant roots.

Gardeners and landscapers rely on this calculation to avoid the two common mistakes of ordering mulch: buying too little and running out mid-project, or over-ordering bulk material that then has to be stored or disposed of. Because bag sizes vary by brand and region (commonly 2 cubic feet in the US), converting a bed's raw volume into an exact bag count depends on knowing the bag size you're buying.

Enter your bed's length, width and the mulch depth you want, along with your bag size, and this calculator gives you the total volume needed and how many bags to buy.