Decomposed Granite Calculator
Decomposed granite is weathered granite screened down to a gravel-and-fines mix that packs into a firm, walkable surface. Work out how many cubic yards or tons you need below.
Sets a typical depth — tweak anything below.
For a 20 ft × 10 ft area at 2 in deep, order about 1.36 cubic yards (1.89 US tons) of decomposed granite.
Estimates only. Densities vary by moisture, compaction and supplier — confirm quantities before ordering.
What is decomposed granite?
Decomposed granite — DG — is granite that has weathered in place until it crumbles, then screened to size. What you buy is a mix of small angular granite chips and the fines that came off them, usually gold, tan or brown. Those fines are the whole trick: they fill the gaps between the chips, so a compacted DG path sets up firm enough to walk, roll a wheelbarrow, or push a stroller on — something loose gravel never does.
What is decomposed granite used for?
It's the default path and patio surface across California and the Southwest, and the standard finish for xeriscaping and drought-tolerant gardens. It also does driveways, dog runs, and the ground under fire pits and seating areas. Three grades exist: natural DG (loose, cheapest), stabilized DG (mixed with a binder so it holds together), and resin-coated DG (the hardest and most expensive).
How much does decomposed granite weigh?
A cubic yard of decomposed granite weighs about 1.39 US tons — roughly 1650 kg/m³, or about 103 lb/ft³. Moisture and compaction shift this, so the calculator applies this density and lets you change it in the extra options if your supplier quotes a different figure.
Coverage by depth
| Depth | Coverage per ton | Coverage per cubic yard |
|---|---|---|
| 1 inch | ~233 sq ft | 324 sq ft |
| 2 inches | ~116 sq ft | 162 sq ft |
| 3 inches | ~78 sq ft | 108 sq ft |
| 4 inches | ~58 sq ft | 81 sq ft |
| 6 inches | ~39 sq ft | 54 sq ft |
Based on about 1650 kg/m³. Actual coverage varies with compaction and moisture.
Common mistakes to avoid
- Guessing the depth. Too shallow and the material shifts and shows the ground beneath. Most surface layers want 2–4 inches; load-bearing bases are built up thicker.
- Forgetting to convert inches to feet. Depth is quoted in inches but volume math is in feet — 4 inches is 0.33 ft, not 4. The calculator handles this, but hand estimates often don't.
- Skipping the waste allowance. Ground is never perfectly flat and material settles once it's placed. Order 5–10% extra so a small shortfall doesn't trigger a second delivery.
- Using the wrong density. Each material weighs differently, so tonnage can be off by 20%+ if you use a generic figure. Pick the right material and adjust the density if your supplier differs.
- Buying bags for a big job. Bagged material costs far more per cubic yard than bulk. Past roughly one cubic yard, a bulk delivery is almost always cheaper.
Frequently asked questions
Does decomposed granite track into the house?+
Yes, and this is the complaint nobody warns you about before you buy it. The same fines that make DG pack firm also stick to shoes, paws and bike tires, and natural DG will put a film of gold dust on your floors for as long as you own it. It's worst in dry weather and right after installation. Stabilized DG cuts it down a lot because the binder locks the fines in place — if your DG path leads to a door, pay for the stabilized version or plan on a serious doormat and a lot of sweeping.
Does decomposed granite get muddy?+
Natural DG softens in heavy rain and the surface gets greasy underfoot — it doesn't turn to soup like bare dirt, but it's not pleasant, and puddles sit where the surface isn't graded. It also erodes: a natural DG path on any real slope will wash into gullies and end up at the bottom of your yard. Stabilized DG holds up to both. If your path is flat and covered, natural is fine; if it's exposed or sloped, stabilize it.
How deep should decomposed granite be?+
2 inches compacted for a path or patio, 3 inches for something you'll drive on, laid over a compacted base rather than straight onto soft soil. Don't go deeper thinking it'll wear better — thick DG never compacts through and stays soft on top. It's better as two thin compacted lifts than one thick one, and each lift needs dampening and rolling.
Do you need to stabilize decomposed granite?+
It depends on where it goes. Flat, low-traffic, away from doors — natural DG is fine and it's half the cost. Anywhere that slopes, gets heavy rain, sees wheelchairs or strollers, or connects to a doorway, the stabilized version is worth it: it resists erosion, tracks far less, and stays firm when wet. Stabilizer is usually a powder binder mixed in dry before you compact and water it.
Decomposed granite or gravel for a path?+
DG if you want a surface you can walk normally on, gravel if you want drainage and don't mind the shifting. DG compacts into something close to a hard path, which is why it's the accessible choice for strollers and wheelchairs. Regular gravel and pea gravel stay loose forever — better for drainage, worse for walking. The trade-off is that DG's fines are what makes it firm and also what makes it track and erode.
How much does a yard of decomposed granite weigh?+
About 1.4 US tons a cubic yard — roughly 2,800 lb — which puts it in the same range as crushed stone. It's sold both ways: by the ton at most quarries, by the cubic yard at landscape suppliers. Work out both above and quote whichever number your supplier asks for.