Measurement guide
Measure once, estimate with a practical buffer.
Bulk material calculators are only as good as the measurements and assumptions entered into them.
Basic area measurement
For rectangular areas, measure the length and width in feet. For irregular areas, break the project into smaller rectangles, calculate each one, then add the totals.
Depth measurement
Enter depth in inches. Mulch, rock, soil, sand, and gravel projects often use shallow depths, so an inch or two can change the final order.
Ordering buffer
Add a small buffer when edges are irregular, the base is uneven, or the material may settle. A 5-10% buffer is common for planning, but supplier advice should win.
Formula used
For most loose materials, cubic yards = length in feet x width in feet x depth in inches / 324.