Mulch Depth Calculator
Calculate how many cubic yards or bags of mulch you need for any bed.
Bed dimensions
Mulch depth & type
Your estimate
Cubic yards
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cu yd (bulk)
Bags needed
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bags
Bed area
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sq ft
Bed area—
Mulch depth—
Volume required—
Cubic yards (bulk delivery)—
Bags (— cu ft each)—
Bags vs. bulk mulch — which is better?
For small beds under 50 sq ft, bagged mulch is usually more convenient and cost-effective once you factor in delivery charges. For larger projects — anything over 3 cubic yards — bulk delivery from a landscape supplier almost always works out cheaper per cubic foot and saves you hauling dozens of bags.
One cubic yard of bulk mulch covers approximately 100 sq ft at 3 inches deep. Most landscape suppliers have a 1–2 yard minimum delivery, so plan your project with that in mind.
Frequently asked questions
How deep should mulch be?
2–3 inches is the sweet spot for most garden beds. It suppresses weeds, retains moisture, and regulates soil temperature without smothering plant roots. Avoid piling mulch against tree trunks or plant stems — keep a 2-inch gap around them.
How many bags of mulch equal a cubic yard?
13.5 bags of 2 cu ft mulch equal one cubic yard (27 cu ft). If you're buying 3 cu ft bags, you need 9 bags per cubic yard. For small jobs, bags are fine; for anything over 3 yards, bulk delivery is almost always cheaper.
Does mulch depth change for different materials?
Yes — fine-textured mulches like shredded hardwood or cocoa hulls compact more, so 2 inches works well. Coarser materials like wood chips or pine nuggets need 3–4 inches to be effective at weed suppression.
How often should I replace mulch?
Most organic mulches break down within 1–2 years. Rather than removing old mulch, just topdress with 1–2 inches of fresh mulch each season. Use the "refresh existing" option in this calculator for that scenario.