How this raised-bed material calculator works
cubic feet = length × width × depth(in) ÷ 12 × number of bedsbags = ceiling(cubic feet × settling factor ÷ bag size)Understanding your result
Mulch, topsoil, compost, garden mix, and potting media have different uses and settle differently. Measure the empty depth actually being filled; do not automatically fill an entire tall bed with premium soil.
Frequently asked questions
How many bags fill a raised bed?
Divide adjusted cubic feet by the volume printed on the bag and round up. Weight is not a reliable volume conversion because moisture and density vary.
Should I add extra for settling?
Loose organic material commonly settles, but the amount depends on composition, moisture, compaction, and time. Use the adjustable factor as a purchasing allowance, not a guarantee.
Methodology & data sources
Important garden-use disclaimer
Volume estimate only. Confirm material type, drainage, soil testing, plant needs, contamination risks, structural bed loading, and bag volume before purchase.