Paver base calculator for Montana

The compacted stone layer below the pavers helps keep a patio flat in five years. Calculate the tons needed here.

Enter your project dimensions

Length (feet)

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Width (feet)

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Diameter (feet)

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Depth (inches)

Enter a depth between 0.25 and 24 inches

Material

Add 5% extra for compaction & spillage

The support stone costs much less per square foot than the pavers, yet failed patios usually trace back to that lower layer. This calculator estimates compacted crusher run or a similar mix at 1.5 tons per cubic yard. Use 4 inches for pedestrian areas and 6-8 for vehicles, with the +10% compaction allowance already selected. Bedding sand is separate: keep it to a firm 1-inch layer and use its own calculator.

Base sizing

Start with the paved footprint in feet, extending it 6 inches beyond each exposed paver edge. That added base supports the edge restraint.
Use 4 inches of compacted material under patios and walkways, 6 under driveways or clay soil, and 8 under driveways where the ground is soft.
To get yards, divide cubic feet by 27. Multiply that result by 1.5 for tons, then turn on the +10% allowance.

Tons = (Base area sq ft × Compacted depth in ÷ 12) ÷ 27 × 1.5 × 1.10
Excavation depth = base + 1" bedding + paver thickness − reveal

Project depth and coverage

Project	Compacted base depth	1 ton covers
Walkway or garden path	4 inches	≈ 54 sq ft
Patio or seating area	4-6 inches	≈ 43 sq ft
Driveway with cars	6-8 inches	≈ 31 sq ft
Clay or soft subgrade	add 2 inches + fabric	n/a

Excavation layers from lawn to finished paver

Find excavation depth by adding all the layers together. A common patio has 4 inches of base, 1 inch of bedding sand, and a 2 3/8 inch paver finished even with the lawn. That comes to a 7.5-inch excavation, adjusted for any reveal above grade. Put the target depth on a stake and check it during digging. Going too deep means extra soil to haul away, which the Dirt Calculator can calculate in reverse, plus more stone needed to bring the grade back up.

Base installation practices

Place the material in 2-inch lifts, using a plate compactor after lightly misting each lift. Base compacts tighter when damp than when dry.
Build the compacted base with a 2-3% slope leading away from the house. The bedding sand and pavers will mirror the grade below.
Install edge restraint on the compacted base rather than lawn soil. The 6-inch extension provides the support beneath it.
For Montana gumbo clay, put woven geotextile beneath the base. It keeps aggregate from being pushed down into the subgrade through each wet season.
Do not make up for shallow base with extra sand. A deep sand bed shifts and can leave the patio surface wavy.

Reusing old pavers: check the base

When an existing patio is being lifted and re-laid, the base may be reusable. Remove the pavers, rake away the old bedding sand, then check the base. If it remains level, firm, and drains well, install a new 1-inch bedding layer instead, reducing the stone order to a tenth of a new build. If there are low areas, soft spots, or standing water, remove the base as well. Leaving a failed base in place puts the same problem beneath the replacement pavers.

Example: a 16 x 12 patio

For 192 square feet of pavers, allow the 6-inch extension on three exposed sides and use 210 as the base footprint. With 4 inches of compaction, the calculation is 210 x 0.333 = 70 cubic feet = 2.6 cubic yards, or roughly 3.9 tons and 4.3 after the allowance. Order 4.5 tons of crusher run, along with 0.9 tons of bedding sand from the Paver Sand Calculator, in one free delivery. Have the material dropped after excavation, because a stone pile left on the lawn for two weeks can kill a rectangular patch of grass.

Questions on base depth, excavation, and tonnage

How can I calculate the paver base quantity?

Add a 6-inch border to the paved area, multiply by the compacted depth in feet, divide the result by 27, multiply by 1.5 tons, then add 10%. A 10 x 10 patio with 4 inches of base needs about 2.2 tons, so order 2.5.

Will 2 inches of paver base work?

For foot traffic, Four compacted inches is the minimum base. Two inches only levels the surface and does not provide support. Reducing the base commonly leads to low spots and pavers that shift or rock.

What base depth do pavers need?

Patios and paths need four compacted inches. Use 6-8 for surfaces carrying cars, with 2 extra inches on clay or wet ground. In Montana's freeze-thaw conditions, base depth matters.

What excavation depth is needed for pavers?

Calculate excavation by adding the base, 1 inch of bedding, and paver thickness, then subtracting the reveal above grade. For standard 2 3/8 inch pavers over a 4-inch base, dig about 7.5 inches below the finished elevation.

For a paver base, crusher run or screenings?

Make crusher run, also called road base, the structural course for the full 4-plus inches. Use screenings only as a thin leveling layer on top of compacted base. Screenings by themselves retain water and can pump when loaded.

Can pavers be installed without a base?

A sound existing concrete slab can take pavers with a bedding layer and drainage gaps. Soil cannot. Pavers laid directly on dirt move with frost heave and rain, often showing the damage in one season.

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The surface shows the work below it.

Order crusher run and screenings by the ton along with bedding sand.

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