Mulch & Topsoil Calculator
Calculate how much mulch, topsoil, gravel, or sand you need. Enter area and depth to get cubic yards, cubic feet, and bag counts.
Estimates only. Always verify quantities with a professional before purchasing materials. Building projects must comply with local codes and regulations.
About Mulch & Topsoil Calculator
This mulch calculator estimates how much mulch, topsoil, gravel, or sand you need for a landscaping project. Enter the area dimensions and desired depth to get results in cubic yards, cubic feet, bag counts, and estimated weight. It supports multiple areas with individual and combined totals, plus material-specific depth recommendations.
How the Calculation Works
| Step | Formula | Example (10 ft x 20 ft bed, 3 in mulch) |
|---|---|---|
| Area | Length x Width | 10 x 20 = 200 sq ft |
| Volume (cubic feet) | Area x Depth (in feet) | 200 x 0.25 = 50 cu ft |
| Volume (cubic yards) | Cu ft / 27 | 50 / 27 = 1.85 cu yd |
| Bags needed (2 cu ft bags) | Cu ft / Bag size | 50 / 2 = 25 bags |
| Weight estimate | Cu yd x Weight per yard | 1.85 x 600 = ~1,110 lbs |
Recommended Depth by Material
| Material | Recommended Depth | Purpose |
|---|---|---|
| Wood chip mulch | 2-4 inches | Weed suppression, moisture retention, aesthetics |
| Bark mulch | 2-3 inches | Decorative beds, trees, shrubs |
| Rubber mulch | 1-3 inches | Playgrounds, high-traffic areas (does not decompose) |
| Topsoil | 4-6 inches | Lawn repair, new garden beds, filling raised beds |
| Compost | 1-3 inches | Top-dressing lawns, enriching garden beds |
| Pea gravel | 2-3 inches | Pathways, drainage, decorative ground cover |
| Crushed stone | 3-4 inches | Driveways, walkways, drainage base |
| Sand | 1-2 inches | Paver base, levelling, play areas |
| River rock | 2-4 inches | Decorative landscaping, erosion control |
Material Weight and Density
| Material | Weight per Cubic Yard | Weight per Bag (2 cu ft) | Notes |
|---|---|---|---|
| Wood chip mulch | 400-800 lbs | 20-40 lbs | Lighter when dry, much heavier when wet |
| Bark mulch | 500-700 lbs | 25-35 lbs | Medium weight, decomposes over 1-2 years |
| Topsoil | 1,800-2,200 lbs | ~40 lbs | Screened topsoil is denser than unscreened |
| Compost | 1,000-1,600 lbs | ~30 lbs | Varies widely by composition and moisture |
| Pea gravel | 2,500-2,800 lbs | ~50 lbs | Heavy - consider delivery for large quantities |
| Sand | 2,400-2,700 lbs | 50 lbs | Standard play sand bags are typically 50 lbs |
Coverage Reference (One Cubic Yard Covers)
| Depth | Coverage Area | Typical Use |
|---|---|---|
| 1 inch | 324 sq ft | Light top-dressing, compost |
| 2 inches | 162 sq ft | Light mulch layer, sand levelling |
| 3 inches | 108 sq ft | Standard mulch depth, gravel pathways |
| 4 inches | 81 sq ft | Thick mulch, topsoil for new beds |
| 6 inches | 54 sq ft | Raised bed fill, deep topsoil layer |
Bags vs Bulk Delivery
| Option | Typical Cost | Best For | Considerations |
|---|---|---|---|
| Bagged (2 cu ft) | $3-8 per bag | Under 2 cubic yards | Convenient, easy to transport in a car, but more expensive per yard |
| Bagged (3 cu ft) | $4-10 per bag | Under 2 cubic yards | Fewer bags needed, still car-friendly |
| Bulk delivery | $25-60 per cubic yard + delivery | 3+ cubic yards | Much cheaper per yard, but needs driveway space for dump |
| Pickup truck load | $25-60 per cubic yard (no delivery fee) | 1-3 cubic yards | Saves delivery fee if you have a truck; one yard weighs 400-2,800 lbs |
Mulching Tips
| Tip | Why It Matters |
|---|---|
| Keep mulch 2-3 inches from tree trunks | "Volcano mulching" against the trunk causes rot and pest problems |
| Do not exceed 4 inches depth | Too-thick mulch suffocates plant roots and prevents water penetration |
| Refresh annually | Organic mulch decomposes and thins over time; top up each spring |
| Lay landscape fabric under gravel | Prevents gravel from sinking into soil and weeds from growing through |
| Order 5-10% extra | Uneven ground, settling, and spreading losses mean you always need a little more |
For general volume conversions to cubic yards, the cubic yards calculator handles any material. To measure your garden bed area, the square footage calculator converts dimensions to square feet. All calculations run in your browser with no data stored.
Frequently Asked Questions
How much mulch do I need for a 10x10 area?
For a 10x10 foot area at 3 inches deep, you need about 0.93 cubic yards, which is roughly 13 bags of 2-cubic-foot mulch. At 4 inches deep, you need 1.23 cubic yards or about 17 bags.
How many bags of mulch are in a cubic yard?
There are about 13.5 bags of 2-cubic-foot mulch in one cubic yard (27 cubic feet per yard divided by 2 cubic feet per bag). If you are using 3-cubic-foot bags, you need 9 bags per cubic yard.
How deep should mulch be applied?
Apply mulch 2-4 inches deep for garden beds and around trees. Keep mulch a few inches away from plant stems and tree trunks to prevent rot. For playgrounds, 6-12 inches is recommended for safety.
What is the difference between mulch and topsoil?
Mulch sits on top of soil to retain moisture, suppress weeds, and regulate temperature. Topsoil is nutrient-rich soil used to fill, level, or improve existing soil for planting. They serve different purposes and have different weights per cubic yard.
How much does a cubic yard of gravel weigh?
A cubic yard of gravel weighs approximately 2,800 pounds (about 1.4 tons). This varies by gravel type - pea gravel is lighter around 2,500 lbs, while crushed stone can be heavier at 3,000+ lbs per cubic yard.
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