Mulch & Compost Calculator

How the Mulch & Compost Calculator Works

This calculator computes the exact volume of mulch, compost, topsoil, gravel or sand you need based on your area dimensions and desired depth. Enter a rectangular area (length x width), a circular area (diameter), or type in square footage directly for irregular shapes. The tool instantly converts your measurements into cubic feet, cubic yards, number of standard 2 cu ft bags, total weight and cost estimates. All calculations run entirely in your browser with no data sent anywhere.

How Much Mulch Do You Need?

The amount of mulch depends on your area size and desired depth. For most flower beds and garden borders, 2 to 3 inches of mulch is ideal. Vegetable gardens benefit from 3 to 4 inches of compost or organic mulch. Pathways and play areas need 4 to 6 inches for good weed suppression and safety. A 200 square foot area at 3 inches deep needs about 50 cubic feet or 1.85 cubic yards of material. One cubic yard of mulch typically covers 108 square feet at 3 inches deep.

Bags vs Bulk Delivery — Which Is Cheaper?

For small areas under 1 cubic yard, buying bags from your local garden center is convenient and requires no minimum order. For larger projects exceeding 2 cubic yards, bulk delivery saves 30 to 50 percent compared to bags. Bulk mulch is sold by the cubic yard and most suppliers deliver with a 2 to 5 yard minimum. Delivery fees range from $50 to $100 depending on distance. The break-even point where bulk becomes cheaper is typically around 1.5 to 2 cubic yards depending on local pricing.

Weight by Material Type

Different materials have very different weights. One cubic yard of wood mulch weighs 400 to 800 pounds, while topsoil weighs around 2,200 pounds and gravel or sand can weigh up to 2,700 pounds per cubic yard. This matters when planning transport — a standard pickup truck can carry about 1 to 2 cubic yards of mulch safely but only about half a cubic yard of gravel. Compost falls in the middle at roughly 1,000 pounds per cubic yard. Always check your vehicle weight rating before hauling heavy materials.

Tips for Applying Mulch and Compost

Apply mulch 2 to 4 inches deep around trees, shrubs and flower beds. Keep mulch 3 to 6 inches away from tree trunks and plant stems to prevent rot. For weed suppression, lay landscape fabric or cardboard under the mulch layer. Refresh organic mulch every 1 to 2 years as it decomposes. Compost can be mixed into soil at a 25 to 30 percent ratio or spread as a 2 to 3 inch top dressing. Fall is the best time to apply compost to garden beds so it breaks down over winter and is ready for spring planting.