Mulch & Gravel Calculator

A mulch and gravel calculator converts the area and depth of your landscape beds into cubic yards, cubic feet, bag counts, and weight — so you know exactly how much material to order before you head to the garden center or call a bulk delivery service. Ordering too little means a second trip; ordering too much wastes money and leaves you with heavy bags to store or dispose of.

Mulch, gravel, topsoil, and decorative rock are sold by the cubic yard in bulk and by the bag at retail stores. One cubic yard equals 27 cubic feet — enough to cover 108 square feet at 3 inches deep, which is the recommended depth for most organic mulches. That context helps you quickly understand why large landscape beds almost always make bulk delivery the more economical option.

Beyond aesthetics, proper mulching provides real measurable benefits for your landscape. A 2–4 inch layer of wood mulch can reduce soil moisture loss by up to 70%, meaning less frequent watering and lower water bills. Mulch also moderates soil temperature — keeping roots cooler in summer and warmer in early spring — and suppresses weed growth that would otherwise compete with your plantings for nutrients and water.

Getting your mulch or gravel quantity right is a two-step process: measure your beds, then input the numbers here.

1. Measure your bed area. For rectangular beds, measure length and width in feet. For irregularly shaped areas, break them into rough rectangles and add the areas together, or measure the total square footage directly.
2. Choose your input method. Use "Length x Width" for simple rectangular beds. Use "Total Square Feet" if you've already calculated or measured the area directly.
3. Set the depth. Wood mulch: 2–3 inches for annual refresh, 3–4 inches for new beds. Gravel and pea gravel: 2–3 inches. River rock: 2–3 inches. Topsoil for raised beds: 6–12 inches.
4. Select the material. Each material has different density, which affects weight, delivery cost, and price per cubic yard. The calculator adjusts weight and cost estimates automatically based on your selection.
5. Compare bulk vs. bagged. The results table shows the cost difference between bulk delivery and purchasing retail bags. For projects over 3 cubic yards, bulk is almost always cheaper — often by 40–60%.

• Keep mulch away from tree trunks. The classic "mulch volcano" piled against a tree trunk traps moisture and invites rot and pests. Maintain a 3–6 inch gap around the base of any tree or shrub.
• Refresh, don't pile. You don't need to remove old mulch every year. Raking and fluffing existing mulch, then adding 1–2 inches on top, is sufficient for most annual maintenance and costs far less than a full replacement.
• Use landscape fabric strategically. Fabric under gravel and rock helps prevent weeds from growing up through the material and keeps decorative stone from sinking into the soil over time. Fabric under organic mulch can actually impede water and air penetration — many gardeners skip it under wood chips.
• Account for compaction with gravel. Gravel settles and compacts after installation and rain. For a walkway or driveway base, order 10–15% more than the calculator suggests to account for settling.
• Bulk delivery saves money at scale. Retail mulch bags (2 cubic feet) cost $4–$7 each, equivalent to $54–$95 per cubic yard. Bulk mulch delivered runs $25–$50 per cubic yard. At 5+ cubic yards, the savings typically cover the delivery fee with money to spare.