Mulch & Gravel Calculator
Find out exactly how much mulch, gravel, or landscape rock you need. Get results in cubic yards, bags, or tons for easy ordering.
How to Calculate Mulch or Gravel
To find out how much mulch or gravel you need, measure the length and width of the area in feet and decide on the depth in inches. Multiply length by width to get the square footage, then multiply by the depth (converted to feet by dividing by 12) to get cubic feet. Divide by 27 to convert to cubic yards, which is how landscape materials are typically sold in bulk.
Recommended Depths by Use
| Application | Recommended Depth | Material |
|---|---|---|
| Weed prevention | 2–3 inches | Mulch |
| Garden beds | 3–4 inches | Mulch |
| Walkways / Pathways | 2–3 inches | Gravel or Pea Gravel |
| Driveways | 4–6 inches | Gravel or Decomposed Granite |
| Decorative areas | 1–2 inches | River Rock |
Mulch vs. Gravel: Which to Choose?
Mulch is ideal for garden beds and around plants because it retains moisture, regulates soil temperature, and breaks down over time to add nutrients to the soil. It needs to be replenished every 1–2 years. Gravel and stone are better for pathways, driveways, and drainage areas because they're permanent, don't decompose, and provide better drainage. They cost more upfront but last indefinitely.
Tips for Ordering Materials
- Order 10% more than your calculated amount to account for settling and uneven terrain.
- For bulk delivery, most suppliers sell by the cubic yard. One cubic yard covers about 162 sq ft at 2 inches deep.
- Bagged material is more expensive per unit but easier for small projects and tight access areas.
- Measure your area carefully — irregularly shaped areas can be broken into rectangles and added together.
- Check if your supplier charges a delivery fee and whether there's a minimum order for bulk delivery.
Frequently Asked Questions
For most garden beds and landscaping, 2-3 inches of mulch is ideal. Use 2 inches for weed prevention around established plants and 3-4 inches for garden beds. Avoid going deeper than 4 inches, as excessive mulch can suffocate roots and trap too much moisture. For gravel and decorative stone, 1-2 inches is typically sufficient.
To calculate cubic yards, multiply your area's length by width (in feet) to get square footage, multiply by your desired depth (in feet), then divide by 27. For example, a 20x10 ft area at 3 inches deep needs: 200 sq ft x 0.25 ft = 50 cu ft / 27 = 1.85 cubic yards. One cubic yard covers about 162 sq ft at 2 inches deep.
One cubic yard equals 27 cubic feet, so it takes 13.5 standard 2-cubic-foot bags to equal one cubic yard. Buying mulch in bulk by the cubic yard is typically 50-70% cheaper per unit than buying bags, making bulk delivery the better option for projects needing more than 2-3 cubic yards.
The best time to apply mulch is mid to late spring, after the soil has warmed up. Mulching too early in spring can delay soil warming and slow plant growth. Fall is also a good time to mulch, as it helps insulate plant roots over winter. Avoid mulching when the ground is frozen or waterlogged.
Organic mulch like wood chips and bark needs to be refreshed every 1-2 years as it decomposes. You can top off thinning areas annually rather than doing a full replacement. Inorganic materials like gravel and river rock are permanent and only need occasional raking to maintain appearance. Rubber mulch lasts 10+ years but does not add nutrients to the soil.