Gravel & Mulch Calculator

Calculate cubic yards, tons, bags needed, and cost. Results update instantly.

ft
ft
in
$
Area
120 sq ft
Rectangle: 12 ft × 10 ft
Cubic Feet
30.00
Cubic Yards
1.11
Weight (lbs)
2,850
Weight (tons)
1.43
0.5 cu ft Bags
60
Cost Estimate
$44.44

How to Calculate Gravel, Mulch, or Topsoil

Whether you are filling a garden bed with mulch, laying a gravel driveway, or topping off a raised planter with topsoil, the calculation follows the same three steps: find the area, choose a depth, and convert to cubic yards. This calculator handles all four common area shapes and seven material types, and updates every result the moment you change any input.

Step 1 — Measure Your Area

Choose the shape that best describes your project. For rectangles and squares, measure length and width in feet. For a circle (round flower bed, tree ring), measure the radius from the center to the edge. For a triangle, measure the base and the perpendicular height. If your space is L-shaped or otherwise irregular, break it into simple shapes, calculate each separately, and add the results — or use the irregular option to enter a total square footage you measured or estimated yourself.

The area formulas used by this calculator are:

Rectangle: Area = Length × Width
Circle: Area = π × Radius²
Triangle: Area = 0.5 × Base × Height

Step 2 — Choose a Depth

Depth (also called coverage depth or layer thickness) is entered in inches. Standard recommendations by material:

  • Mulch: 2–3 inches for garden beds; 3–4 inches for tree rings. Avoid going deeper than 4 inches — thick mulch can suffocate roots and encourage rot.
  • Pea gravel / river rock: 2–3 inches for pathways and decorative beds. 4–6 inches for driveways.
  • Crushed stone: 4 inches for base layers, 2–3 inches for top dressing.
  • Sand: 1 inch for leveling pavers; 2–4 inches for playgrounds; 4–6 inches as a drainage layer.
  • Topsoil: 2–3 inches to top-dress existing lawn; 6–8 inches for new lawn establishment; 12+ inches for raised garden beds.
  • Decomposed granite: 2–3 inches for pathways and patio surfaces.

Step 3 — Convert to Cubic Yards

Landscape materials are sold in cubic yards when delivered in bulk. One cubic yard equals 27 cubic feet. The volume calculation is:

Volume (cu ft) = Area (sq ft) × Depth (in) ÷ 12
Volume (cu yd) = Volume (cu ft) ÷ 27

Always add 10–15% to your calculated amount to account for settling, uneven ground, and edges. It is much cheaper to have a little extra delivered than to pay for a second trip.

Weight by Material Type

Knowing the weight helps you plan delivery logistics — most pickup trucks can carry about half a cubic yard of heavy material like gravel (around 1,400 lbs) and about one cubic yard of light material like mulch (around 540 lbs). The densities used in this calculator reflect typical dry conditions:

  • Pea gravel: 95 lb/cu ft (about 2,565 lb/cu yd)
  • Crushed stone: 100 lb/cu ft (about 2,700 lb/cu yd)
  • River rock: 100 lb/cu ft (about 2,700 lb/cu yd)
  • Mulch: 20 lb/cu ft (about 540 lb/cu yd)
  • Topsoil: 75 lb/cu ft (about 2,025 lb/cu yd)
  • Sand: 100 lb/cu ft (about 2,700 lb/cu yd)
  • Decomposed granite: 95 lb/cu ft (about 2,565 lb/cu yd)

Wet material can weigh 20–30% more. If your material will be wet during delivery or spreading, account for this when planning truck payloads.

Bags vs Bulk Delivery

A standard bag of landscape material at a home improvement store typically contains 0.5 cubic feet. This calculator shows how many bags you would need, but it is important to know that buying in bags costs 2–4 times more per cubic yard than bulk delivery from a landscape supplier. Bags make sense for small touch-up jobs under about 0.5 cubic yards. For any project larger than a few square feet at 3 inches deep, call a local landscape supply yard and ask about bulk pricing — the savings are substantial.

Cost Estimation

The cost estimate in this calculator multiplies your calculated cubic yard volume by the price per yard you enter. Typical bulk prices by material in 2025:

  • Mulch (dyed or natural): $25–55 per cubic yard
  • Pea gravel: $30–55 per cubic yard
  • Crushed stone: $35–65 per cubic yard
  • River rock: $50–100 per cubic yard
  • Topsoil: $20–45 per cubic yard
  • Sand: $25–50 per cubic yard
  • Decomposed granite: $35–70 per cubic yard

Prices vary widely by region, supplier, and delivery distance. Most suppliers charge a delivery fee of $40–100 on top of the material cost. For very large orders (5+ yards), ask about discounts for a full truckload.

Frequently Asked Questions

Multiply your area in square feet by the desired depth in feet (depth in inches divided by 12), then divide by 27 to convert to cubic yards. For example, a 200 sq ft bed at 3 inches deep needs 200 × (3/12) ÷ 27 = 1.85 cubic yards of mulch. This calculator does all that arithmetic for you the moment you enter your dimensions.
The weight of a cubic yard of gravel depends on the material type. Pea gravel weighs about 2,565 lbs (1.28 tons) per cubic yard. Crushed stone and river rock weigh about 2,700 lbs (1.35 tons) per cubic yard. Sand weighs roughly 2,700 lbs per cubic yard. Mulch is much lighter at about 540 lbs (0.27 tons) per cubic yard.
For landscaping gravel or river rock, 2–3 inches provides good coverage and weed suppression. Driveways need 4–6 inches of compacted gravel. Mulch for garden beds should be 2–3 inches deep — any deeper can cause root rot. Decomposed granite pathways work well at 2–3 inches. Sand for leveling or playgrounds is typically 2–4 inches deep.
A standard 0.5 cubic foot bag covers a very small area. There are 54 half-cubic-foot bags in one cubic yard (27 cubic feet ÷ 0.5 = 54 bags). For large projects, ordering bulk material by the cubic yard from a landscape supplier is significantly more economical than buying bags.
Bulk landscape mulch typically costs $25–50 per cubic yard. Pea gravel and crushed stone run $30–60 per cubic yard. River rock is usually $50–100 per cubic yard depending on size and color. Topsoil costs $20–45 per yard. Decomposed granite runs $35–70 per yard. Prices vary significantly by region and delivery distance. Buying in bags at home improvement stores can cost 2–3 times more per cubic yard than bulk delivery.