Decomposed Granite Calculator for Yards and Tons by Depth
Use finished area multiplied by compacted depth to get cubic yards of decomposed granite, then add about 10% for compaction and delivery loss; 1 cubic yard is often about 1.3 to 1.5 tons, depending on moisture and product. Ordering too little means short coverage, thin spots, and another delivery charge. This guide shows the DG formula, a worked example, and how to convert cubic yards to tons and bags.
How much decomposed granite do I need?
The short answer is area × compacted depth, then add a waste allowance. Decomposed granite is weathered granite rock that breaks into smaller pieces, and it is used for driveways, paths, patios, and garden walkways. A practical order starts from the finished installed thickness, not the loose pile depth.
Start with finished area and compacted depth
Compacted depth is the finished installed thickness after rolling or tamping. Standard compacted depth for pathways and patios is 2 to 3 inches. Driveways typically need 3 to 4 inches of compacted DG. Those depths drive the order quantity more than the square footage alone.
Use the basic volume formula
Use this formula: cubic feet = square feet × depth in feet. Then convert cubic feet to cubic yards by dividing by 27. For a project around 400 square feet at about 3 inches deep, the amount is roughly 3.7 cubic yards before waste.
Add a small waste allowance for cuts and loss
DG compresses 15% to 25% when properly compacted, so the loose order must be larger than the final bed. A simple order allowance is about 10%, though some jobs may need more on sloped installs, curved edges, or where base material takes up part of the planned thickness.
The average cost of decomposed granite is $60.
How do I calculate decomposed granite for square feet and depth?
Convert inches to feet first, then multiply by area, then convert cubic feet to cubic yards. That sequence keeps the unit math consistent. A rectangle is the easiest place to start because length × width gives area, and depth stays as a separate input.
Convert inches of depth to feet
Use this rule: depth in feet = depth in inches ÷ 12. So 2 inches is about 0.17 feet, 3 inches is about 0.25 feet, and 4 inches is about 0.33 feet. That conversion matters because cubic feet and cubic yards are volume units, not coverage claims.
Turn cubic feet into cubic yards
One cubic yard equals 27 cubic feet. Divide the calculated cubic feet by 27 to get yards for bulk ordering. If the supplier prices by the ton, the yard figure still helps as the first step before density conversion.
Work through a rectangle example
For a patio around 20 ft × 15 ft at about 3 inches compacted depth, the calculation works out to roughly 2.8 cubic yards before waste, or a little over 3 cubic yards after adding about 10% for waste.
Using a common ordering assumption of about 1.4 tons per cubic yard, that 3.06 cubic yards is about 4.3 tons. If the product is around 1.5 tons per cubic yard, the same order is roughly 4.5 to 4.6 tons. Moisture content and particle size change the conversion, so yards and tons should not be treated as identical.
How much decomposed granite per square foot should I order?
Per-square-foot coverage depends on finished depth, density, and compaction. At 2 inches, the coverage is higher than at 4 inches because the volume per square foot is lower. Supplier charts often flatten those differences, which can mislead buyers who do not match the chart to the installed depth.
Typical coverage at 2, 3, and 4 inches
| Compacted depth | Cubic feet per sq ft | Cubic yards per 100 sq ft | Approximate coverage note |
|---|---|---|---|
| 2 in | 0.167 | 0.62 | Higher coverage, thinner bed |
| 3 in | 0.250 | 0.93 | Common path and patio depth |
| 4 in | 0.333 | 1.23 | Lower coverage, heavier order |
Why coverage changes with compaction and density
Loose DG settles during installation. That shrinkage means a pile that looks full can still finish thin after compaction. Because DG compresses 15% to 25% when properly compacted, the loose coverage chart must be translated into finished depth before placing an order.
When a supplier’s coverage chart can mislead you
A chart that says “one ton covers 100 square feet” may only be true at 3 inches compacted depth, which matches. The same ton will not cover the same area at 4 inches. Stabilized DG and resin-coated DG can also differ in density and usage, so the product type matters.
How do cubic yards and tons compare for DG ordering?
Cubic yards and tons are not interchangeable. Yards measure volume, while tons measure weight. The conversion depends on density, moisture, and particle size. One cubic yard can equal about 1.4 tons for standard ordering assumptions, and a cubic yard of half-inch decomposed granite weighs approximately three tons in another published assumption.
Why density drives the yard-to-ton conversion
Density changes when moisture content changes, and finer or coarser particles pack differently. That is why one supplier may quote a lower tonnage per yard than another. Buyers should use the supplier’s density data when available, then keep the order in the unit the supplier actually sells.
Use a tonnage estimate from cubic yards
If a project needs 3.06 cubic yards, multiply by a supplier’s ton-per-yard figure. At 1.4 tons per cubic yard, the order is 4.28 tons. At 1.5 tons per cubic yard, it is 4.59 tons. That range is normal when moisture and grading differ.
Build a supplier-ready summary with both units
Supplier-ready orders should show both cubic yards and tons. That avoids a conversion error at pickup or delivery. It also keeps the material-only price separate from the delivered price, which matters because delivery fee can materially change the final project cost.
What depth should DG be installed at?
For most paths and patios, the standard compacted depth is 2 to 3 inches. For driveways, 3 to 4 inches is more typical. DG is used for roads and driveways, but it is not the first choice for every traffic condition, and the surface type should match the use case.
Recommended compacted depth for paths and patios
Paths and patios usually sit at 2 to 3 inches compacted. That range gives enough material for a stable finish without overbuilding the layer. Stabilized DG is recommended for walkways, patios, and residential driveways when a firmer surface is needed.
Recommended compacted depth for driveways
Driveways typically need 3 to 4 inches of compacted DG. For heavier traffic, stabilized DG or resin-coated DG may be a better fit than plain natural DG. Natural DG averages $60 per ton, while stabilized DG costs $100 to $185 per ton.
When DG is a poor choice for traffic or slopes
DG can move on steep slopes, in drainage paths, and under repeated turning loads if the base is not built correctly. Where vehicle traffic is frequent, the product and base need more care than a simple depth rule can provide. If the project is heavily sloped, another surface may be a better fit.
DG calculator worksheet: finished area, compaction, and delivery
This worksheet separates the job into three parts: finished-area math, loose-to-compacted adjustment, and supplier-ready summary. Use it for rectangle and circle projects alike. It also keeps delivery fee separate from the material-only amount, which prevents cost confusion.
Section 1: finished-area math
- Rectangle: length × width = square feet.
- Circle: 3.14 × radius × radius = square feet.
- Depth: convert inches to feet by dividing by 12.
- Volume: square feet × depth in feet = cubic feet.
- Yards: cubic feet ÷ 27 = cubic yards.
Circle example: a 12 ft diameter garden walkway has a 6 ft radius. Area = 3.14 × 6 × 6 = 113.04 sq ft. At 2.5 inches deep, depth = 0.208 ft. Volume = 113.04 × 0.208 = 23.5 cubic feet, or 0.87 cubic yards before waste.
Section 2: loose-to-compacted adjustment
Add about 10% for compaction and handling loss unless the supplier specifies a different allowance. For the circle example, 0.87 cubic yards × 1.10 = 0.96 cubic yards. If the product compacts more heavily or the install includes cuts, the allowance should be higher.
That adjustment matters because DG compresses 15% to 25% when properly compacted. The loose load must therefore exceed the finished volume. Without that margin, the final surface can end up short, especially near edges and around curves.
Section 3: supplier-ready cubic yards, tons, and delivery cost
| Project | Finished size | Compacted depth | Order quantity | Estimated tons | Material cost range | Delivery fee |
|---|---|---|---|---|---|---|
| Rectangle patio | 20 ft × 15 ft | 3 in | 3.06 yd³ | 4.3 to 4.6 tons | $172 to $367 at $40 to $80 per ton | Add separately |
| Circle walkway | 12 ft diameter | 2.5 in | 0.96 yd³ | 1.3 to 1.4 tons | $52 to $112 at $40 to $80 per ton | Add separately |
For a 400-square-foot area, published cost data places the project roughly between $160 and $900 including depth and delivery. That wide spread reflects depth, product type, and delivery distance. The average cost of decomposed granite is $60, while decomposed granite costs between $40 and $80 per ton.
Frequently asked questions
How much decomposed granite do i need calculator
A calculator should ask for square feet, finished depth in inches, and product type. It should then convert inches to feet, multiply by area, divide by 27, and add a waste allowance. If it also shows tons, it should state the density assumption used for that conversion.
How much decomposed granite per square foot
The amount per square foot depends on compacted depth. At 2 inches, the volume is 0.167 cubic feet per square foot. At 3 inches, it is 0.25 cubic feet. At 4 inches, it is 0.333 cubic feet. Coverage changes with compaction and density, so one fixed number is not reliable.
How much decomposed granite do i need
Start with area, pick the finished compacted depth, and calculate volume. Then add about 10% for compaction and waste. If the project has curves, cuts, or a sloped base, the extra margin may need to be larger than 10% to avoid short coverage.
How much decomposed granite calculator
A good calculator should separate finished volume from loose order quantity. It should show cubic feet, cubic yards, and tons, because suppliers may sell by the yard or by the ton. It should also separate material-only cost from delivered cost so the final number is not understated.
How to calculate decomposed granite
Multiply square feet by depth in feet to get cubic feet, then divide by 27 to get cubic yards. After that, apply a compaction allowance and convert to tons if the supplier prices by weight. Keep the depth in compacted form, not loose pile form, or the result will be too small.
decomposed granite calculator tons
To convert yards to tons, use the supplier’s density assumption. A standard ordering figure can be about 1.4 tons per cubic yard, but the actual value changes with moisture content and particle size. That is why a ton calculator should never treat every DG product the same.