Mulch Quantity
Free Mulch Quantity calculator with clear step-by-step results.
About Mulch Quantity
Bulk mulch is sold by the cubic yard and bagged mulch by the cubic foot, so the useful answer is both. Bed area times depth in feet gives cubic feet; dividing by 27 converts to cubic yards. One cubic yard covers about 160 ft² at 2 inches or 108 ft² at 3 inches. A settling allowance is included because shredded bark loses noticeable loft in the first few weeks.
Formulas
Volume
Cubic feet = area (ft²) × depth (in) ÷ 12 × (1 + settling)
Bulk and bags
Cubic yards = cubic feet ÷ 27; bags = ceil(cubic feet ÷ bag size)
Worked example
With the default values below, Mulch Quantity returns Mulch Required of 5.09. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Bed areaminimum 0 ft²
- 500 ft²
- Mulch depthaccepts 0.5–12 in
- 3 in
- Bag sizeminimum 0.5 ft³
- 2 ft³
- Settling allowanceaccepts 0–40 %
- 10 %
Results
- Mulch Required
- 5.09 yd³
- Volume
- 137.5 ft³
- Bags to Buy
- 69 bags
- Volume (metric)
- 3.89 m³
Step by step
- 1Values used
- 2Volume
- 3Bulk and bags
- 4Mulch Required= 5.09 yd³
- 5Volume= 137.5 ft³
- 6Bags to Buy= 69 bags
- 7Volume (metric)= 3.89 m³
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- Coverage figures are approximate and vary with material, moisture and how firmly the mulch is spread. Confirm volumes with your supplier before ordering bulk loads.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Coverage figures are approximate and vary with material, moisture and how firmly the mulch is spread. Confirm volumes with your supplier before ordering bulk loads.
Frequently Asked Questions
How deep should mulch be?
Two to three inches is the usual recommendation. Deeper than about four inches can hold water against stems and starve roots of air, and mulch should be kept clear of trunks rather than mounded against them.
How many bags equal a cubic yard?
Thirteen and a half 2 ft³ bags, or nine 3 ft³ bags. Bulk delivery is almost always cheaper above roughly two cubic yards.
Does mulch need topping up every year?
Organic mulches break down, so most beds need a thinner refresh layer each season rather than a full re-mulch. Measure the depth you already have and only make up the difference.