Gravel and stone: volume, tonnage, bases, drainage stone and haulage

What the gravel calculators cover

Stone is bought by weight and laid by volume, and most of this page is the bridge between the two. The surface pages turn an area and a depth into a volume and a weight for a driveway, a path, a base under pavers or a bedding course. The drainage pages count the stone round a drain, behind a wall or in a trench, and the permeable paving pages count the bedding and the jointing stone. The conversion pairs turn a volume into a weight and back for each material: gravel, pea gravel, crushed granite, crushed limestone, recycled aggregate, rip rap, river rock, slate chippings, sand and fill sand.

Two pages are about the stone itself and not the quantity. The fineness modulus page takes a sieve analysis and gives the modulus of ASTM C136, and the moisture correction page corrects a concrete mix's batch weights for the moisture in the sand and stone. The haulage pages count dump truck loads from a bed capacity, and the stockpile page finds a pile's volume from the distance round its toe and the material's angle of repose.

How the answers are worked out

Mass is volume times density, and the density is the part that varies. The gravel calculator uses a loose bulk density as delivered, while the base tonnage pages use the in-place density of a compacted dense-graded base, citing the Wisconsin DOT Standard Specifications for the conversion. The pages say that density varies with stone type, grading and moisture, so the supplier's ticket weight governs. Each conversion pair carries a planning density with a note on why it differs: rounded stone packs less densely than angular crushed stone, slate chippings pack differently from rounded stone, recycled aggregate is slightly lighter than virgin stone, and damp sand is heavier and bulks up in volume.

The open-graded bedding page follows ASCE/T&DI 68-18 for permeable interlocking pavement: a screeded layer of open-graded No. 8 stone laid to a uniform thickness and not compacted before the units are set. It takes the loose bulk density from the supplier, and a densification allowance that it calls a rule of thumb, to be checked against the first bay laid. The hardscape page takes its sub-base depths for pedestrian and vehicular paving from BS 7533 and ICPI guidance, and its bedding layer from ICPI Tech Spec 2.

Drainage stone is the volume of the space less what is not stone. The French drain page subtracts the pipe's own volume from the trench; the retaining wall drainage page counts a drainage zone as wall length times height times width; the weeping tile page counts pipe segments along a foundation perimeter; and the geocell page counts the infill of a gravity wall as its whole cross-section and not one course, because the wall resists overturning by its own mass.

Units and documents by market

The market setting chooses the system the answers appear in: cubic yards and short tons for the United States, cubic metres and tonnes for the other three markets, each answer restated in the other system. The gravel calculator gives its answer in the tons or tonnes you order in, and the truck load calculator counts in whichever measure the hauler quotes, since beds are quoted in cubic yards in North America and in cubic metres in metric markets. The table shows which documents the calculators cite for each market.

Allowance, density and loose volume

Counts round up because loads and tons are ordered whole. The French drain page adds a waste allowance for trench irregularities and settling, the mulch and gravel page uses the standard landscaping formula for cubic yards from area and depth, and the stockpile page returns loose volume, the material as it sits in the pile. That volume is neither the bank volume the material occupied in the ground nor the compacted volume it occupies once placed, and the page says the three differ by a substantial margin for most materials.

The order the questions come in

Start from the surface. The area and the depth the surface needs give a volume, and the base and bedding courses are counted apart from the wearing course because each has its own depth. Density then turns each volume into the tonnage you order, the truck load page turns it into trips, and the stockpile page checks what arrived. The grading and moisture pages are checks on the stone itself, for the mix it goes into, and the drainage pages are counted wherever water has to leave.

What the calculators leave to others

Depths on these pages are inputs with a stated starting point. The gravel page describes its driveway depth as common residential practice, the paver base page as a typical installation, and the hardscape page cites BS 7533 and ICPI guidance, so set the depth your specification asks for. The rip rap page counts the stone volume as the slope area times the average layer depth, and the layer depth belongs to the design. The conversion pages use planning densities, not specifications, and defer to the supplier.

Whole jobs, taken off

A job takeoff asks for the dimensions once and returns every line the job needs, each from its own calculator. These are the ones where gravel is a main line.

• Paver patio

  Pavers, base, bedding sand, edging, jointing sand and sealer for a laid patio, with the stone base counted from the same area.

Read an answer backwards

When you start from what you hold and want to know what it will cover, these pages run the same calculators in reverse.

• How much bed will a yard of mulch cover?
• How much ground will my gravel cover?
• How long a French drain will my gravel fill?
• How long a retaining wall will my drainage gravel back?

Worked examples

A job worked through with its inputs and its working shown, so you can see the figures before you enter your own.

• Gravel driveway

  A gravel driveway worked from the slope and the swell of the dug soil to the truck loads, the geotextile, the base tonnage and the surface stone, in the order they are bought.

• Paver patio

  A paver patio worked from the dig depth and the spoil to the base, the bedding, the pavers and the sealer, so the stone below the surface is counted with the units on it.

• A single-car gravel driveway, in tons and yards

  Gravel for a single-car driveway 60 by 10 ft

Reference tables

• Production rates by operation

  How long each operation takes one person, in person-hours per unit of work.

• Bulk densities of construction materials

  What a cubic metre of loose material actually weighs, in both systems, as this site's calculators compute it.

Guides

The practice behind the numbers: how the work is done, what goes wrong and how to check it.

• Laying a Gravel Driveway

  Angular stone locks and rounded stone rolls — how to build a gravel drive layer by layer so it stays where you put it.

• Buying Bulk Material by the Load

  Three suppliers quoting per load, per tonne and per cubic yard, reduced to one rate you can actually compare — and how much to order once the allowance is honest.

• Laying a Paver Patio or Drive

  A hardscape field guide organised around the load path: the compacted base is the real pavement, and the pavers are only its wearing course.

• Open-Graded Bedding: The Layer That Has to Stay Open

  Fifty millimetres of single-sized stone that must never be compacted, walked on, or topped up with anything a quarry has not washed.

• Permeable Paving and Storage Below It

  A permeable pavement is a tank built out of gaps, and every layer from joint aperture to subgrade earns its keep by void ratio.

• Draining a New Driveway So It Stays Permitted Development

  A front drive whose water reaches the road is not permitted development: the porous surface, the receiving border, the application, and proving which you built.

• Building a Gabion Wall

  A gabion is a container, not a structure. The trade sits in mesh aperture, in the fill's placed bulk density, and in what the bottom course beds on.

• Founding and Anchoring a Shed or Pergola

  A flat-pack kit settles everything except the runner grid under it, the post positions it has to land on, and the hold-down it ships without.

• Sizing a Soakaway From a Percolation Test

  Three timed water drops in a trial pit give one infiltration rate. Storage volume, crate count and the half-drain check all fall out of it.

Terms

• Sub-base / hardcore
• Aggregate size designations
• Bulking and swell
• Ton / tonne
• Hardstanding and paved area
• Sand grades
• Soakaway and infiltration structures

How the numbers are worked out

Every calculator names the method it uses and the standard or guidance behind it. These are the methods the most of the calculators above rest on, and the published documents they cite.

Methods

• Unit Conversion, Exactness and Rounding

  Why most conversion factors carry no uncertainty at all, which ones hide a material assumption, and why converting a measurement can never make it more precise than it was. Applies to 20 of the calculators above.

• Volume from Geometry, and the Order That Follows

  Why the depth carries almost all the risk in a volume, why an excavation holds far more than its plan area suggests, and why a bag's yield is not its weight divided by a density. Applies to 10 of the calculators above.

• Bulking, Swell and the Three Volumes of One Soil

  Why a hundred cubic metres dug out becomes a hundred and twenty-five to cart away and ninety when it is put back, and why a cut-and-fill balance struck in the wrong state does not balance. Applies to 2 of the calculators above.

• Concrete Mix Design and Fresh-Concrete Behaviour

  Why a litre of water added on site costs strength permanently, why yield is the sum of absolute volumes rather than of loose ones, and why strength is a function of temperature and time together rather than of age. Applies to 2 of the calculators above.

• Quantity, Waste and Rounding

  Why a material count is a ceiling function rather than a division, and why the waste factor — not the geometry — carries the risk. Applies to 2 of the calculators above.

• Pavement Layers, Subgrade and Soil-Supported Structures

  Why a pavement's thickness is decided by the ground rather than by the traffic, why an SPT blow count read straight off a log is systematically wrong, and why a flexible culvert is really a soil structure. Applies to 1 of the calculators above.

Standards cited

• ACI 211.1

  Cited by 1 of the calculators above.