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Mulch & Soil Calculator
How many yards of mulch for your garden beds? Enter the bed size and depth — get cubic yards and bag counts.
Bed measurements
1 cubic yard = 27 cubic feet. Standard mulch depth is 3 inches.
How to calculate mulch by hand
- Multiply length × width × (depth ÷ 12) → cubic feet.
- Divide by 27 → cubic yards.
- For bags: divide cubic feet by the bag size and round up.
Example: 20×4 ft bed, 3 in deep → 20 × 4 × 0.25 = 20 cu ft → 0.74 cubic yards → 10 bags (2 cu ft).
Mulch FAQs
How deep should mulch be?
3 inches is standard — enough to block weeds and hold moisture without smothering roots. Keep mulch a few inches away from tree trunks and stems.
Is bulk mulch cheaper than bags?
Usually yes. Above ~3 cubic yards, bulk delivery beats bag prices, and many yards deliver free over a minimum. Bags win for small beds and easy transport.
How often should I re-mulch?
Once a year in spring. Mulch decomposes — top up to maintain 3 inches rather than replacing it all.
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Frequently asked questions
How deep should mulch be?
Spread mulch 2 to 3 inches deep. Less than 2 inches lets weeds through; more than 4 inches can suffocate plant roots.
How many bags of mulch are in a cubic yard?
One cubic yard equals about fourteen 2-cubic-foot bags, or nine 3-cubic-foot bags of mulch.
What is the difference between mulch and topsoil?
Mulch sits on top of soil to retain moisture and block weeds. Topsoil is used to build up or level the ground before planting.
How often should I re-mulch?
Top up mulch once a year, usually in spring. Organic mulch breaks down over time and improves the soil as it decomposes.