A stone patio is built in layers: a 16 × 12 ft patio needs about 2.4 cubic yards (3.7 tons) of crusher run for the 4-inch base, plus 0.6 cubic yards (0.9 tons) of bedding at 1 inch. Run the calculator once per layer, switching material and depth each time.
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Stone Patio Calculator Guide
Price a stone patio as one number and the number will be wrong, because a patio is a stack of three different materials at three different depths. The structural base carries the load, the bedding levels the surface, and the stone on top is the only part guests ever see. This calculator handles the whole stack one pass at a time: enter the patio footprint, then run it once per layer, switching the material and depth to match the row you are pricing.
The default — crusher run at 4 inches — is the base layer, because that is where quantities are largest and shortfalls hurt most. A base delivered two tons light gets discovered after the excavation is open and the skid steer has gone home, which is the most expensive possible moment to learn subtraction.
What Are the Layers of a Stone Patio?
| Layer | Depth | Material | For a 150 sq ft patio |
|---|---|---|---|
| Subgrade | — | Compacted native soil | two compactor passes |
| Base | 4 in | Crusher run | ≈ 1.9 yd³ / 2.9 tons |
| Bedding | 1 in | Stone dust or concrete sand | ≈ 0.5 yd³ / 0.7 tons |
| Surface | 1.5–2 in | Flagstone, pavers, cobbles | ≈ 1.4–1.8 tons of flag |
Excavation depth is the sum of the stack — about 7 inches below finished grade for 2-inch surface stone — and the hole should extend 6 inches past the patio edge so the perimeter sits on base rather than crumbling soil. Patios hosting hot tubs or heavy planters deserve a 6-inch base; the extra two inches cost less than re-leveling a sunken corner.
Getting the Slope Right
Every layer of the stack is built parallel to the finished surface, and the finished surface must fall 1 inch for every 8 feet, directed away from the house. Set the slope with string lines before the first ton of base arrives: stakes at the house wall and the far edge, lines pulled at finished height, so every screed and compaction pass has a reference. A 16-foot-deep patio drops 2 inches from the wall to the far edge — invisible to the eye, decisive in a thunderstorm.
Build the fall into the compacted base, not the bedding. If the base is flat and the bedding is wedge-shaped, bedding depth varies across the patio and the surface will settle unevenly into the thick end. Compact the base in 2-inch lifts, checking the string at each pass, and the thin bedding layer above stays a uniform inch everywhere.
Deep-dive each layer with its own tool: the crusher run calculator covers the base material in detail, and the flagstone calculator converts your surface area into tons of stone by thickness. Order base and bedding together — they arrive on the same truck and the delivery fee only stings once.
Frequently Asked Questions
What are the layers of a stone patio?
From the ground up: compacted subgrade, 4 inches of compacted crusher run base, 1–2 inches of bedding sand or stone dust, then the surface stone itself. Each layer has a different material and depth, which is why you calculate them separately.
How much slope does a patio need?
Fall of 1 inch for every 8 feet, always directed away from the house. Build the slope into the compacted base — trying to create fall in the bedding layer means uneven bedding depth, and the pavers or flagstone will settle unevenly to match.
How deep do I excavate for a stone patio?
Add the layers: 4 inches of base, 1 inch of bedding, and the stone thickness — about 7 inches below finished grade for 2-inch flagstone. Measure down from a string line at finished height, not from the existing lumpy soil.
Is crusher run or #57 stone better for a patio base?
Crusher run compacts into a dense, semi-rigid layer and is the traditional choice under patios. Washed #57 builds an open-graded base that drains instantly and resists frost heave, but it must be paired with chip bedding rather than sand.