Mulch Calculator

How to measure mulch coverage

1. Measure each bed (length x width), add them for total area.
2. Exclude hardscape and established groundcover you won't cover.
3. Choose a depth based on your goal (appearance vs weed suppression).
4. For irregular shapes, over-measure slightly instead of trying to be perfect; waste is usually cheaper than a second trip.
5. If the bed has low spots you want to fill, estimate that volume as soil (not mulch) and keep mulch as a consistent top layer.
6. If you have multiple beds with different goals, estimate them separately and choose different depths if needed.

Assumptions to double-check

• Depth is average depth after raking; mulch can settle after watering.
• Different mulch types have different coverage per yard/bag.
• Sloped beds often need a bit more to look evenly covered.
• Edge definition (steel edging, stone borders) affects how cleanly you can spread to a consistent depth.
• Fresh mulch can settle noticeably after the first rain; a small buffer helps maintain target depth.
• Wind, rain, and foot traffic can move mulch from edges and paths; plan extra for early touch-ups.
• You will usually keep mulch thinner right around plant stems/trunks, so your effective bed average depth is not uniform.
• If you are mulching near a house, keep clearance from siding and vents; this affects how you spread and how deep you can safely go near edges.

Buying tips

• Confirm bag size or bulk yard coverage with your supplier.
• Don't pile mulch against tree trunks (avoid "mulch volcano").
• Order a little extra for touch-ups and areas you may expand later.
• If color matching matters, buy enough at once; bags/lots can vary between shipments.
• Dyed mulch can bleed on concrete or stone after heavy rain; keep a small clearance near hardscape if that matters.
• If you use landscape fabric, pin it well and plan a slightly thicker layer to fully cover the fabric.
• If you have pets/kids, choose a mulch type that fits your use case (splinter risk, dyed mulch preference, etc.).
• Prep first: edge the bed, remove weeds, and rake old mulch flat. Good prep reduces how much new mulch you need to make the bed look even.
• If termites are a concern in your area, avoid piling mulch against the foundation and keep a visible inspection gap.
• If you buy bulk, plan where the pile will be dumped and how far you’ll wheelbarrow it—labor can drive the real cost.

Common mistakes to avoid

• Using an unrealistic depth (too thin for weed suppression or too thick around plants).
• Forgetting settling; mulch can look thinner after rain and raking.
• Not accounting for irregular bed edges and obstacles that change effective area.
• Putting mulch over weeds without prep (many weeds will grow right through if you don't clear first).
• Burying tree flare and plant crowns under mulch—keep mulch off trunks and stems.
• Using mulch to level an area and then wondering why it washes away or looks uneven after the first rain.
• Choosing a mulch type that doesn’t match the use case (large nuggets on slopes, or splintery mulch in play areas).