Paver Base Calculator: Sizing the Layer Nobody Ever Sees
Enter your project dimensions
The patio that sinks a corner in its third winter almost never failed at the pavers. It failed under them, in a base that was too thin, too narrow, or laid straight onto Piedmont clay that had nowhere to send its water. This paver base calculator will size that layer honestly, but it can only size what you tell it about, and the thing readers most often get wrong is the footprint: a base measured to the edge of the paving is already too small before anybody starts digging.
What this estimate cannot know about your subgrade
The tool works on the volume you describe. It has no way of seeing what is under the turf. Red clay that holds water after a wet spell will take a base deeper than the same patio would need on sandy Coastal Plain ground, and it will also want woven geotextile between the soil and the stone so that the stone does not migrate down into it over a couple of wet seasons.
That decision sits with you and it changes the order, usually by two inches across the whole area. Make it before you calculate, not after the stone is on the drive. A base that is one lift short cannot be rescued later by a deeper bed of sand, because sand moves under load and pavers follow it.
The base is bigger than the patio, by six inches all round
Measure the paved area first, then add six inches beyond every exposed edge. A patio with the house along one side has three exposed edges; a freestanding walkway has all four. That shoulder is not spare material. It is the ground the edge restraint sits on, and edge restraint spiked into lawn soil instead of compacted stone is the second most common reason a patio spreads at the corners.
Work in feet, converting inches into decimals, so six inches of shoulder on each side of a ten foot width makes the base eleven feet wide.
Crush and run at 1.50 tons a yard, and why screenings will not stand in
The structural course is Crush and Run or ABC Stone, the graded material with fines that locks up under a plate compactor. This site publishes it at about 3,000 pounds a cubic yard, which is 1.50 tons, and that is the figure the tool applies.
Screenings are a little lighter at roughly 2,900 pounds, or 1.45 tons, and their fineness tempts people into treating them as a base. They are not one. A thin screening course over compacted base is a fine leveling layer; screenings carrying the whole load will trap water and pump under a wheel. Put the depth into the stone that binds, and keep screenings to the last half inch of leveling if you use them at all.
Handing the paver base calculator a footprint that includes the shoulder
Choose Rectangle, Circle or Multiple areas at the top of the page. Enter the base dimensions, not the paving dimensions, as feet. Depth goes in as inches between 0.25 and 24, and it means the compacted thickness rather than the loose pile. Set the material, leave "add 10% extra for compaction & spillage" ticked, and read cubic yards, tons and cubic feet. "Email my quote" keeps the numbers where you can find them at the product page.
A 14 by 12 patio against the back of the house, on clay
An illustrative example. The paving is 14 feet along the house by 12 feet out from it, so 168 square feet. The house takes one 14-foot edge; the other three are exposed, so the base runs 15 feet by 12.5, which is 187.5 square feet.
Clay subgrade means four inches plus two, so six compacted inches. 187.5 x 6 / 12 = 93.75 cubic feet. 93.75 / 27 = 3.47 cubic yards. At 1.50 tons a yard that is 5.21 tons, or 5.73 with the ten percent ticked.
The dig is the base plus one inch of bedding sand plus the paver itself. With a common 2 3/8 inch paver, that comes to 6 + 1 + 2.375 = 9.375 inches below the finished surface, less whatever reveal you want the paving standing above the lawn. Mark that depth on a stake and check it as you dig, because soil taken out beyond the mark has to be replaced with stone you then have to buy.
Four inches for feet, six to eight for anything with wheels
A walkway or a garden path is fine at four compacted inches. A patio or seating area runs four to six. Anything a car parks on wants six to eight, and clay or soft ground adds two inches to whichever band you are in, along with the fabric underneath. Coverage moves fast with depth: a ton of base covers roughly 54 square feet at four inches, 36 at six and 27 at eight, so the difference between a path and a parking area is not a rounding error.
Rolling two inches at a time, and the wheelbarrow you keep in reserve
Compact in two-inch lifts with a plate compactor, misting each lift lightly first, since damp base tightens far better than dry. Pitch the finished base two to three percent away from the house and let the sand and pavers take that same fall. Set the edge restraint on compacted stone, out on the shoulder you paid for.
If you are lifting an old patio and the base under it is still level, firm and draining, you may only need fresh bedding sand over it, which turns a full order into a fraction of one. Low spots, soft patches or standing water mean that base comes out and gets rebuilt, because leaving it in reproduces the same failure under new pavers.
Round the order up and keep a wheelbarrow-load back. Take the tonnage to the product page to choose a quantity and a delivery date, and size the bedding course separately in the paver sand calculator. A drive rather than a patio is better handled in the crusher run calculator, which works in lanes and turnarounds. Delivery is arranged at checkout by ZIP code, and the truck needs clear access to a spot where the pile can sit off the lawn; delivery and site access says what that means in practice. If the hole you have dug is telling you something about the soil, ask about your subgrade before the stone is ordered.
Common questions
My patio has a curved front edge. How do I get a base area out of that?
Square the curve off into rectangles that just contain it, using Multiple areas, and remember to keep the six-inch shoulder outside the curve. A little surplus stone on a base is a far better outcome than a shortfall, and the offcut goes under the edge restraint anyway.
The ABC stone under my old pavers looks untouched. How do I test it before ordering?
Check it before you decide. Pull the pavers, rake off the old bedding sand, and walk the base. If it is level, firm and drains, you need bedding sand and very little else. If a straight edge shows dips or your boot sinks anywhere, price the base as new work, because a patched failure comes back.
The crush and run runs out before the far edge of the patio. What then?
You either stop the patio short or thin the layer to make it stretch, and the thin part is where the settling starts. Bulk stone is bought by the ton, so round the calculated figure up to the next quarter or half ton and leave the ten percent on.
Where does this tonnage usually go wrong, the shoulder or the dig depth?
The arithmetic is exact for what you enter. It is only as good as the base footprint you gave it, so check the shoulder is included and that the depth is the compacted one. Digging deeper than planned is the other common gap, since every inch of over-excavation becomes stone you did not calculate.
Do I order Crush and Run or ABC Stone, and where does the bedding sand come from?
The base tonnage goes to Crush and Run or to ABC Stone, whichever name you have been working from, and you choose the quantity and the delivery date there. Bedding sand is a separate order from Mason Sand, sized at exactly one inch.
Related calculators
The pavers get the compliments. The base earns them.
Crusher run and screenings by the ton, free delivery, ordered together with your bedding sand.