How to use this mulch calculator
Enter the size of each bed, set how deep you want the mulch, and this mulch calculator instantly shows how much mulch you need in cubic yards, cubic feet and bags. Gardening in odd shapes? Add a bed for each rectangle, circle or triangle and the totals add up for you. Already know your square footage? Choose Area and type it straight in. It's the fastest way to answer the only question that matters at the garden center: how much mulch do I need, and what will it cost?
Cubic yards, cubic feet and bags — all at once
Mulch is measured three ways depending on where you buy it, so this tool shows all three together. Bulk mulch is priced by the cubic yard, big-box stores sell it by the bag, and the underlying math is in cubic feet. The formulas are simple: cubic feet = square feet × (depth in inches ÷ 12), cubic yards = cubic feet ÷ 27, and bags = cubic feet ÷ bag size, rounded up. So a yards-of-mulch calculator, a mulch calculator in square feet, and a how-many-bags-of-mulch calculator are really the same calculation — we just surface every number so you never have to convert by hand.
Measuring beds, including circles
For rectangular beds, multiply length by width. For round beds, use the circle option and measure straight across the middle — that makes this a circle mulch calculator too, using area = π × radius². For triangles, it's base × height ÷ 2. Break a complicated border into a few simple shapes, add a bed for each, and read the combined total in cubic yards and cubic feet.
Bags or bulk — and how much mulch to buy
Once you know the volume, the next question is cost. Type in a price per bag and a price per cubic yard and the calculator tells you which is cheaper and by how much, so it doubles as a how-much-mulch-to-buy calculator rather than just a volume tool. As a rule of thumb, bulk delivery wins for big landscape jobs while bags are easier for small beds and tight access. Add a waste factor — 10% is a sensible default — to cover settling, spillage and uneven ground.
How deep should mulch be?
Two to three inches suits most beds: enough to lock in moisture and block weeds without smothering roots. Each season, refresh back up to about three inches rather than piling onto old, matted layers, and keep mulch pulled a couple of inches away from trunks and stems. Playgrounds are the exception, needing 6–12 inches of loose fill for fall protection.
A landscape mulch calculator for every material
Different materials behave differently, so we built dedicated tools with the right defaults — for rubber, bark, playground safety surfacing and decorative rock. Pick the one that matches your project for material-specific depths and packaging, or use this general landscape mulch calculator above for standard wood and organic mulch. No sign-up, no clutter — just the numbers you need to buy the right amount once.