Why measure every bed together
Ordering mulch one bed at a time is where most driveway-sized over-orders come from. Rounding up to a whole bag on each of six beds can add most of a cubic yard of waste; rounding a bulk order up to the supplier minimum on each separate delivery is worse still. Adding the beds first, then applying a single 10% settling buffer to the combined volume, is both cheaper and more accurate.
The calculator sums each bed's area, multiplies by its depth, and converts the total to cubic yards and bags. Add or remove zones as you walk the yard; the running total updates as you go.
How the total is calculated
- Area of each bed — length × width for rectangles (measure irregular beds as a set of rectangles and add them).
- Volume — total area × depth in feet (depth ÷ 12). Beds at different depths are handled per-zone, then summed.
- Buffer — add 10% to the combined volume for settling, spillage, and uneven ground.
- Bags — divide the buffered cubic feet by your bag size (1.5, 2, or 3 cu ft) and round up once, for the whole project.
Splitting an odd-shaped bed into two or three rectangles and adding them is accurate to within a few percent — well inside the margin the 10% buffer already covers.