Paver Base Calculator: Compacted Tons Before the Ground Freezes

Patio work in this state has a calendar, and the calendar is short. The ground has to be thawed enough to dig and dry enough to compact, which puts the honest window somewhere from mid-spring through the fall, and every week of it gets taken up by a stretch of rain that turns an open excavation into a bathtub. The paver base calculator below sits in the middle of that sequence: measure in one dry spell, order in the next, and have the stone on the drive before the digging stops being pleasant.

Working back from the first hard frost

Frost reaches down about 42 inches here, and it does not come out of the ground evenly in the spring. That is the whole argument for base depth. A patio on four compacted inches over sound ground rides the cycle. The same patio on two inches finds its low corner by the second March.

So plan the sequence rather than the day. Excavation, base in lifts, bedding and pavers ideally run in the same stretch of settled weather, because an open dig that fills with water has to be pumped, dried and re-compacted before anything else happens. If the season is getting away from you, it is better to hold the job until spring than to compact a base into saturated till in November.

The six inches of base that sit outside the pavers

Here is where most base orders go wrong. The base is not the size of the patio. It runs six inches past every uncovered paver edge, because that shoulder is what the edge restraint gets spiked into and what stops the outer course from creeping. An edge against the house or an existing wall needs no overhang; a free edge does.

So measure the paved shape, then add a foot to any dimension with two free edges and six inches to any dimension with one. On a 14 by 10 terrace with the house along one long side, that turns 140 square feet of paving into 157.5 square feet of base.

Base, bedding and paver thickness add up to the dig

The excavation depth is a sum, not a rule of thumb: base depth, plus one inch of bedding, plus the paver thickness, minus however much reveal you want the finished surface to stand above the lawn.

For a typical patio that is 4 inches of base, 1 inch of bedding and a 2 3/8 inch paver, which comes to about 7.5 inches below the finished surface. Mark that on a stake, drive it at the low corner and check the dig against it as you go, because over-digging on an older lot means both hauling soil away and buying stone to put the depth back.

Where the till turns to clay or stays wet, the extra two inches and a layer of woven geotextile underneath do more for the finished patio than any amount of care taken with the pavers themselves.

Filling in a 14 by 10 terrace off the back door

An illustration rather than a customer job. Fourteen by ten against the house, so the base footprint is 15 by 10.5, or 157.5 square feet, at 4 compacted inches.

• 157.5 x 4 / 12 = 52.5 cu ft
• 52.5 / 27 = 1.94 cu yd
• 1.94 x 1.50 = 2.92 tons
• With the 10% box ticked: 2.13 cu yd, 3.21 tons

Round that to 3.5 tons of Crusher Run or Processed Gravel, which both weigh about 3,000 lb per cubic yard. The bedding course is separate: the same 157.5 square feet at a strict 1 inch is 13.1 cubic feet, 0.49 cubic yards, about 0.66 tons of sand.

Enter the shape in the tool as a rectangle, or as a circle on its full diameter for a round sitting area, or as up to five areas when a patio and its path are going in together. Dimensions in feet, depth in inches from 0.25 to 24, material selected so the weight is right, and the answer comes back as cubic yards, tons and cubic feet with an option to email it to yourself.

Two-inch lifts and a mist can, once the pile is on the drive

Compact in two-inch lifts rather than one thick layer, and wet each lift lightly first, since damp base knits together far better than dry. Shape a fall of two to three percent away from the house while you are still in the stone, because the bedding and the pavers will follow whatever grade the base sets.

Set the edge restraint on the compacted base, not on lawn soil, which is the second reason for that six-inch shoulder. And resist the temptation to fix a low spot with extra sand later. Sand moves under load. Base does not.

Ordering half a ton you can walk on

Round base tonnage up. The shortfall on a base course shows up as a dip at the far corner, and by the time it appears the pavers are on top of it. A spare half ton goes under the step, into the path, or gets raked into the drive.

One more habit worth having: arrange the delivery for after the excavation, not before. Stone standing on the lawn for two weeks leaves a dead patch, and on a tight older lot the pile is usually in the way of the wheelbarrow route.

Three tools cover a paved surface and they do different jobs. This one sizes the compacted course. The paver sand calculator sizes the one-inch bedding layer and the joint bags. The crusher run calculator is for a drive or pad where nothing is being paved and there is no overhang to add. When the tonnage is settled, set quantity and date on the product page, where delivery is arranged at checkout by ZIP code and the truck needs clear access to a firm place to tip.

Common questions

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