Paver Base Calculator

A paver patio is a sandwich, and the thick slice is the one nobody prices

Under the pavers there is an inch of screeded sand; under the sand there is four to twelve inches of compacted crushed stone. On this patio the sand is 0.44 cubic yards and the stone is 1.78 — four times as much material, and the layer that decides whether the job is still flat in five years. It is also the layer most of the calculators ranking for this search treat as an afterthought.

Six pages were read live for this sheet. Two could not be captured at all and are recorded as unknown, so this is about the four that were readable. One computes a single layer against a fixed density printed in prose with no source. One sells proprietary panels that stand in for four inches of compacted base. One counts pavers and has no depth field at all, despite ranking for paver base calculator. Only one exposes two depth fields with a different default for patios, driveways and heavy load parking — uncited, and the live result was blank in the capture.

The contribution here is narrow: two layers with editable depths and weights from a named table, a traffic class wired to a published minimum, and a section drawn from your own numbers rather than a stock photograph of a gravel pile.

The base course, and the compaction figure this sheet refuses to invent

The depth the sheet opens at is 4 inches because CMHA — the association formed when ICPI merged into NCMA — writes, in Tech Spec 10: Minimum aggregate base thickness for walks should be 4 to 6 in. (100 to 150 mm), driveways 6 to 8 in. (150 to 200 mm), and streets 8 to 12 in. (200 to 300 mm). Thicknesses may be greater depending on site conditions, freezing temperatures, and traffic (typically defined at 18,000 lb. or 80 kN equivalent single axle loads), as well review by a qualified design professional. Read the guide.

Those are minimums, which is why the class select does not overwrite anything. It opens the depth at the low end of its range and raises a warning when the depth you typed falls below it, quoting the figure. Type more and nothing complains: a minimum is not an upper bound.

What this sheet will not do. The same document asks for at least 98 percent of standard Proctor density under walks and residential drives, and modified Proctor for vehicular areas. That says how hard to compact, not how many loose cubic yards build one compacted inch. Caterpillar’s bank column for crushed stone, 4,500 lb per cubic yard, is solid rock in the quarry face, and applying it here would over-order by about two thirds. So no compaction factor is applied by default: the depth you type is the layer you want in place, and any allowance is your own typed percentage. At ten percent this patio orders 1.96 cubic yards instead of 1.78.

The weight comes from one table: Caterpillar’s common materials list, crushed stone at 2,700 lb per cubic yard in the loose column — material already dug and swelled, which is the state a truck dumps in and the state you buy in. The table is here. None of the readable competitors names a source for the density it uses.

One screeded inch of bedding, and where it stops

The bedding field opens at 1 inch. Oregon State University Extension describes screeding sand over lengths of pipe so that this process ensures a uniform layer of sand one inch thick; CMHA puts the same layer at 1 to 1 1/2 in. (25 to 40 mm) uncompacted, so anything from 1 to 1.5 inches is inside both documents. The OSU guide is a homeowner how-to from an extension service, not a paving specification; follow whatever your paver manufacturer prints.

CMHA is blunt about the temptation to use it as a levelling course: Do not use the sand to fill depressions in the base. These eventually will be reflected in the surface of the finished pavement. Fill any depressions with base material and compact. That is the whole argument for sizing the base properly rather than burying its faults in sand.

Bags are counted from the dry sand row, 2,400 lb per loose cubic yard, because water is weight and not volume: 22 bags of 50 lb here, and the bag weight is editable, not a constant we looked up. If the bedding slice is all you are buying, it has its own sheet — the sand calculator, C-103, which links back here for the base. For aggregate that is not under pavers, use the gravel calculator.

Area      A  =  L x W        rectangle
             =  pi x D^2 / 4  circle
             =  B x H / 2     triangle
Base      Vb =  A x db / 12 / 27          (sq ft, in -> cu yd)
Bedding   Vs =  A x ds / 12 / 27
Order     Vo =  V x (1 + allowance / 100) (allowance defaults to 0)
Tons      T  =  Vo x D / 2000             (D = lb per cu yd, loose)
Bags      B  =  ceil( Vso x 2400 / bag weight )
Dig       de =  db + ds + paver thickness (only if you type one)
Loads     N  =  ceil( (Vbo + Vso) / capacity )

Digging to a depth, not to a feeling

The excavation depth is the sum of the three layers, and OSU says so in as many words: by adding together the inches required for the base (4 to 6 inches) the sand bedding (1 inch) and the paver’s thickness. The sheet prints that depth and the volume of soil it takes out, but only once you type a paver thickness. A dig depth that quietly leaves the paver out is a number somebody digs to, and then finds their patio standing proud of the lawn.

With a 2.375 inch paver — a 60 mm unit — this patio digs 7.375 inches, 3.28 cubic yards out. A 3.125 inch, 80 mm paver makes it 8.125 inches and 3.61 cubic yards. That is all the thickness is used for: this sheet does not count pavers.

Worked example: a driveway, and a walkway

1. Driveway, 480 sq ft, class driveway, base typed at 8 in: 11.85 cubic yards, 16 short tons of stone.
2. Bedding at 1 in: 1.48 cubic yards, 1.78 tons, 72 bags of 50 lb if you buy it bagged.
3. At a 12 cu yd truck, base and bedding together: 2 loads.
4. A 120 sq ft walkway, 3 by 40 ft, at the same 4 in: 1.48 cubic yards, 2 tons.

Every line sits on the takeoff tab with its arithmetic attached and exports to CSV.

Frequently asked

How do I figure out how much paver base I need?

Area times base depth. The 144 sq ft patio above at 4 inches is 48 cubic feet, 1.78 cubic yards, 2.4 short tons of crushed stone at 2,700 lb per cubic yard loose. Six inches instead of four makes it 2.67 cubic yards, 3.6 tons.

How much base to put under pavers?

CMHA publishes minimums, not a single number: Minimum aggregate base thickness for walks should be 4 to 6 in. (100 to 150 mm), driveways 6 to 8 in. (150 to 200 mm), and streets 8 to 12 in. (200 t… Walks 4 to 6 in, driveways 6 to 8 in, streets 8 to 12 in — compacted aggregate, under the bedding sand. Choose your class above and the sheet warns you when the depth you typed sits below it.

Can I use 3/4 gravel for paver base?

Nothing this sheet cites names a gradation, so it does not answer that: what it does is price the question. The weight it computes with is Caterpillar's crushed stone row, 2,700 lb per loose cubic yard, and your yard's own figure for whatever they sell as paver base is the one that ends up on the ticket. Ask them by name and by the ton.

How many square feet does one bag of paver base cover?

This sheet counts bags for the bedding sand only, from the dry row: 22 bags of 50 lb for 144 sq ft at 1 inch, about 6.5 sq ft a bag. Crushed stone is ordered by the ton: 2.4 tons here.

Can I skip the gravel and just use sand under pavers?

The two documents behind this sheet both describe a section with a compacted aggregate base under the bedding sand, and CMHA is explicit that the sand is not there to level the base: Do not use the sand to fill depressions in the base. Sheet A-203 sizes both layers so you can see what the base actually costs — 2.4 tons against 0.53 on this patio.

Is 2 inches of sand too much for pavers?

It is more than CMHA asks for: The sand should be screeded to 1 to 1 1/2 in. (25 to 40 mm) uncompacted, consistent thickness. A low spot is fixed in the base, with base material compacted, not with extra sand. Type a bedding depth above 1.5 inches and this sheet flags it.

Limits of this sheet

A-203 turns a plan area and three layer thicknesses into volumes, weights, a bag count, an excavation depth and, if you enter a payload, a number of loads. It does not count pavers, size an edge restraint, rate geotextile or joint sand, count compactor passes, or design a pavement for a soil report. Gradations and code tables stay with their publishers: this sheet links to them. Quantities are for planning and ordering, not engineering.

Sheet A-203 prepared by TakeoffMetric Editorial; no author, credential or field measurement is claimed.