Mulch Calculator

A 10x10 bed at 2 inches deep needs about 0.62 cubic yards of mulch, or 9 two-cubic-foot bags without waste.

Quick answer

A 10x10 bed at 2 inches deep needs about 0.62 cubic yards of mulch, or 9 two-cubic-foot bags without waste.

Volume = length × width × (depth ÷ 12). Divide by 27 for yards, or by the bag size for bags.

More mulch is not better. Over 4 inches can block water and air from reaching roots.

Keep mulch a few inches away from trunks, stems, and the foundation of the house so it does not hold moisture against wood or masonry.

Top up once a year in spring or fall, not every season. The goal is to maintain depth, not bury last year’s mulch.

If the old layer has compacted, fluff it with a rake before adding more.

Bags are easier for small beds and stairway gardens. Bulk delivery is much cheaper for large areas.

Use this calculator to compare both: if you need more than about 14 two-cubic-foot bags, bulk is often the better price.

Note. Keep mulch 2 to 3 inches deep around shrubs and 2 to 4 inches in open beds. Pull it away from trunks and stems.

Two-cubic-foot bags of mulch by bed size and depth, with 10% waste.
Bed size	2"	3"	4"
4 x 8	4	5	7
8 x 8	7	10	13
10 x 10	10	14	19
12 x 12	15	21	28
20 x 20	25	37	49

How many bags of mulch do I need?

A 10x10 bed at 2 inches needs 10 two-cubic-foot bags with 10% waste.

How deep should mulch be?

2 to 3 inches around shrubs and flowers. Deeper mulch can suffocate roots and trap moisture against trunks.

How many bags equal a cubic yard?

Fourteen two-cubic-foot bags, or nine three-cubic-foot bags.

Should I remove old mulch first?

No, just loosen it and keep total depth under 4 inches. If it has matted or grown mold, remove some.

Last updated: 2026-10-29