Compost Calculator

Estimate compost volume, weight, bag count, and cost for gardens, lawns, and raised beds. The calculator uses your area, project type, application rate, and purchase method to turn a planned topdressing depth into practical buying quantities.

How to use this calculator

Choose feet or meters, enter length and width, select the project type, and choose light or heavy application. Then choose bagged compost priced per 1 cu ft bag or bulk compost priced per cubic yard. The result shows estimated cost, area, required depth, volume, weight, and bags when bagged compost is selected.

Formula

Area is converted to square feet, then depth is converted from inches to feet:

$volume\ in\ cubic\ feet = area\ in\ square\ feet \times depth\ in\ inches \div 12$

For a 10 ft by 10 ft new garden at the light 1 inch rate, volume is 8.3 cu ft or 0.31 cu yd. Bagged at 5 dollars per 1 cu ft bag, it rounds to 9 bags for about 45 dollars.

Compost planning

Raised beds use deeper compost than existing lawns, so choose the project type carefully. For neighboring landscape materials, compare organic amendments with the mulch calculator and soil fill with the topsoil calculator.