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Work out aggregate for base course, drainage, foundations and roadworks. Enter your finished compacted depth and this calculates the loose volume you actually need to order — because aggregate shrinks when you compact it, and most calculators quietly ignore that.
Estimate from your inputs. Confirm density and compaction with your supplier or engineer before ordering.
To calculate aggregate, multiply length × width × compacted depth in feet and divide by 27 for cubic yards. Then add a compaction factor of 10–25% because loose aggregate shrinks when compacted, and multiply by about 1.35 for tons. A 12 × 50 ft driveway base 6 in deep needs 11.1 yd³ compacted, so order about 12.8 yd³ loose — roughly 17.2 tons.
Every figure here is derived below. The compaction step is the one that separates a usable estimate from an under-order.
Compaction and waste are not the same thing, and combining them is the most common error in aggregate estimating. Compaction is a physical certainty — the material genuinely occupies less space once rolled, so you need more of it to reach a design depth. Waste is losses: spillage, over-excavation, material left in the truck. Rolling them into one "waste" number, as several popular calculators do, hides the engineering and makes it impossible to reason about either.
Worked example — a 12 × 50 ft driveway base, 6 in compacted, crushed stone. Area = 600 ft². Design volume = 600 × 0.5 = 300 ft³ = 11.11 yd³. With a 15% compaction factor the loose volume is 12.78 yd³, and adding 5% waste gives 13.42 yd³ to order. At 100 lb/ft³ that is 18.1 tons — two dump truck loads. Ignore compaction and you would order 11.7 yd³ and finish roughly an inch shallow.
Real projects showing design volume and the loose volume you actually order, at a 20% compaction factor. Weights are for the loose volume.
| # | Project | Aggregate | Area | Depth | Design yd³ | Order loose | Weight |
|---|---|---|---|---|---|---|---|
| 1 | Residential driveway base | Crusher run | 12 × 50 ft | 6 in | 11.11 | 13.33 yd³ | 24.31 t |
| 2 | Long driveway | MOT Type 1 | 12 × 100 ft | 6 in | 22.22 | 26.67 yd³ | 47.20 t |
| 3 | Parking lot base | Road base | 40 × 60 ft | 8 in | 59.26 | 71.11 yd³ | 129.63 t |
| 4 | Industrial yard | Road base | 60 × 80 ft | 10 in | 148.15 | 177.78 yd³ | 324.08 t |
| 5 | Concrete slab sub-base | Crushed stone | 24 × 30 ft | 4 in | 8.89 | 10.67 yd³ | 14.40 t |
| 6 | Garage floor base | Crushed stone | 20 × 22 ft | 4 in | 5.43 | 6.52 yd³ | 8.80 t |
| 7 | Shed base | Crusher run | 10 × 12 ft | 4 in | 1.48 | 1.78 yd³ | 3.24 t |
| 8 | Warehouse foundation | Road base | 80 × 120 ft | 12 in | 355.56 | 426.67 yd³ | 777.78 t |
| 9 | Patio base | Crushed stone | 16 × 20 ft | 4 in | 3.95 | 4.74 yd³ | 6.40 t |
| 10 | Walkway base | Crushed limestone | 4 × 30 ft | 4 in | 1.48 | 1.78 yd³ | 2.40 t |
| 11 | Paver driveway base | Crusher run | 12 × 40 ft | 6 in | 8.89 | 10.67 yd³ | 19.44 t |
| 12 | Tennis court base | Crushed stone | 60 × 120 ft | 6 in | 133.33 | 160.00 yd³ | 216.02 t |
| 13 | Basketball pad base | Crushed stone | 30 × 50 ft | 4 in | 18.52 | 22.22 yd³ | 30.00 t |
| 14 | French drain | Drainage aggregate | 2 × 40 ft | 12 in | 2.96 | 3.56 yd³ | 4.56 t |
| 15 | Retaining wall drainage | Drainage aggregate | 1.5 × 40 ft | 18 in | 3.33 | 4.00 yd³ | 5.13 t |
| 16 | Foundation perimeter drain | Drainage aggregate | 2 × 120 ft | 12 in | 8.89 | 10.67 yd³ | 13.68 t |
| 17 | Trench backfill | Sand & gravel | 2 × 80 ft | 24 in | 11.85 | 14.22 yd³ | 23.04 t |
| 18 | Pipe surround | Drainage aggregate | 3 × 60 ft | 8 in | 4.44 | 5.33 yd³ | 6.84 t |
| 19 | Soakaway | Drainage aggregate | 6 × 6 ft | 36 in | 4.00 | 4.80 yd³ | 6.16 t |
| 20 | Road sub-base | MOT Type 1 | 20 × 200 ft | 8 in | 98.77 | 118.52 yd³ | 209.76 t |
| 21 | Farm track | Crusher run | 10 × 300 ft | 6 in | 55.56 | 66.67 yd³ | 121.53 t |
| 22 | Rural road repair | Road base | 16 × 150 ft | 8 in | 59.26 | 71.11 yd³ | 129.63 t |
| 23 | Horse arena base | Crushed stone | 60 × 120 ft | 4 in | 88.89 | 106.67 yd³ | 144.01 t |
| 24 | Barn floor | Crusher run | 24 × 36 ft | 6 in | 16.00 | 19.20 yd³ | 35.00 t |
| 25 | Decorative bed | Decorative stone | 10 × 30 ft | 3 in | 2.78 | 3.33 yd³ | 4.50 t |
| 26 | Xeriscape area | Granite aggregate | 25 × 35 ft | 3 in | 8.10 | 9.72 yd³ | 13.52 t |
| 27 | Recycled fill | Recycled aggregate | 30 × 40 ft | 8 in | 29.63 | 35.56 yd³ | 38.96 t |
| 28 | Railway ballast section | Ballast | 8 × 100 ft | 12 in | 29.63 | 35.56 yd³ | 52.74 t |
| 29 | Driveway base (metric) | MOT Type 1 | 3.5 × 20 m | 150 mm | 13.73 | 16.48 yd³ | 29.17 t |
| 30 | Slab sub-base (metric) | Crushed stone | 8 × 10 m | 100 mm | 10.46 | 12.56 yd³ | 16.95 t |
Depths are finished compacted depths. The order column includes 20% compaction but no waste allowance — add yours on top.
The compacted volume your drawing or spec calls for. Use it to check the design, never to place an order.
Design volume plus compaction plus waste. This is the number the supplier needs, and it is always larger.
Aggregate is commonly sold by weight. Confirm whether a quote is per ton or per cubic yard before comparing.
Square feet per ton at your depth. One ton of crushed stone covers roughly 120 ft² at 2 in, or 60 ft² at 4 in.
Quarries know how their material behaves. A spec sheet beats any generic table, especially for MOT Type 1 and recycled aggregate.
No amount of aggregate fixes a soft, wet subgrade. Proof-roll it, dig out soft spots, and lay fabric before you order.
For most residential base work a single well-graded material like crusher run outperforms layering several clean stones.
Delivery is per trip. If you are just over a truckload, trimming the depth an inch often saves an entire delivery charge.
The single biggest error. You finish short of depth and have to order a small, expensive second load.
Single-sized washed stone has no fines to lock it up. It stays loose under load.
The fines that make it a great base are exactly what clogs a drain.
A plate compactor influences 4–6 in. Below that the material stays loose and settles later.
Each swatch is drawn to the typical particle size and angularity, with the density and suggested compaction factor for that material.
Sizes are quoted by nominal maximum particle size, with US number designations in brackets. Larger stone drains better; smaller graded material compacts tighter.
| Size | Metric | US designation | Typical use |
|---|---|---|---|
| Dust / fines | 0–4 mm | Stone dust, screenings | Levelling course, paver joints, top dressing |
| ¼″ | 6 mm | #10 screenings | Fine levelling, path surfacing |
| ⅜″ | 10 mm | #8 / pea size | Thin bedding, decorative, concrete mixes |
| ½″ | 12 mm | #7 | Concrete aggregate, drainage backfill |
| ¾″ | 20 mm | #57 — the workhorse | Base course, slab sub-base, drainage |
| 1″ | 25 mm | #67 | Base course, heavier drainage |
| 1½″ | 40 mm | #4 | Deep base layers, rough fill |
| 2″ | 50 mm | #2 | French drains, culverts, soakaways |
| 3″ | 75 mm | #1 / rip-rap edge | Heavy fill, erosion control, soft ground |
| Aggregate | lb/ft³ | Tons per yd³ | t/m³ | Compaction | ft² per ton @4″ |
|---|---|---|---|---|---|
| Recycled aggregate | 81 | 1.10 | 1.30 | 20% | 74 |
| Drainage aggregate (clean) | 95 | 1.28 | 1.52 | 5% | 63 |
| Crushed stone (#57) | 100 | 1.35 | 1.60 | 15% | 60 |
| Crushed limestone | 100 | 1.35 | 1.60 | 15% | 60 |
| Concrete aggregate | 100 | 1.35 | 1.60 | 10% | 60 |
| Decorative stone | 100 | 1.35 | 1.60 | 5% | 60 |
| Granite aggregate | 103 | 1.39 | 1.65 | 12% | 58 |
| Gravel | 105 | 1.42 | 1.68 | 12% | 57 |
| Ballast | 110 | 1.48 | 1.76 | 10% | 54 |
| Sand & gravel mix | 120 | 1.62 | 1.92 | 18% | 50 |
| MOT Type 1 | 131 | 1.77 | 2.10 | 25% | 46 |
| Crusher run | 135 | 1.82 | 2.16 | 22% | 44 |
| Road base | 135 | 1.82 | 2.16 | 22% | 44 |
Typical estimating values. Density varies by quarry source, gradation and moisture — wet aggregate can weigh 10–25% more. Compaction factors are indicative; use your supplier's or engineer's figure where one exists.
| Application | Compacted depth | Aggregate | Notes |
|---|---|---|---|
| Paver / patio base | 4–6 in | Crusher run, #57 | Plus 1 in bedding sand above |
| Concrete slab sub-base | 4 in | Crushed stone #57 | Clean stone under a vapour barrier |
| Shed / hot tub pad | 4–6 in | Crusher run | Compact in two lifts, check level |
| Residential driveway | 6–8 in | Crusher run, MOT Type 1 | More over soft or clay subgrade |
| Parking area | 8–10 in | Road base, crusher run | Depth follows traffic and axle loads |
| Heavy / industrial yard | 10–14 in | Road base | Engineered design; follow the spec |
| Road sub-base | 8–12 in | MOT Type 1, road base | DOT specification governs |
| French drain | 12+ in | Clean #2 or #57 | Washed, no fines, wrapped in fabric |
| Retaining wall drainage | 12 in behind wall | Clean drainage stone | Full height, with a drain pipe at the base |
| Foundation perimeter drain | 12 in | Clean washed stone | Filter fabric over the top |
| Tennis / sport court base | 6 in | Crushed stone | Tight tolerance — screed carefully |
| Decorative landscape | 2–3 in | Decorative stone, granite | Fabric underneath to suppress weeds |
Add each area for one combined order, using the aggregate type, compaction factor and waste allowance from the calculator above.
Aggregate is the collective term for the granular materials — crushed stone, gravel, sand and recycled equivalents — that make up the bulk of most construction. It is the most extracted material on earth by volume, and almost every road, slab and foundation sits on it. In concrete it typically forms 60 to 75 percent of the volume, which means the aggregate does more of the work than the cement people usually credit.
The material divides into coarse aggregate, retained on a 4.75 mm sieve, and fine aggregate, which passes it. Most of what this calculator handles is coarse aggregate used as base course, drainage and fill.
Aggregate is specified by particle size distribution, determined by sieve analysis. In North America the number system is shorthand for which sieves the material passes: a #57 stone is roughly three-quarter-inch material with fines screened out, a #67 runs to about one inch, and a #2 is around two inches. In the UK and Ireland the equivalent shorthand is a named specification, most commonly MOT Type 1 for sub-base.
The nominal maximum size matters practically. Larger stone drains better and bridges soft ground; smaller graded material compacts tighter and finishes flatter. A base layer should generally use aggregate no larger than about a third of the layer thickness, otherwise it cannot compact properly.
Crushed stone is quarried rock mechanically broken into angular pieces — the general-purpose material for base and drainage. Crushed limestone is the same idea in a softer, paler rock that compacts well. Granite aggregate is harder and more durable for demanding applications. Gravel is naturally occurring and rounded. Crusher run and road base are graded blends of crushed stone and fines that compact into a near-solid mass. MOT Type 1 is the British equivalent, a tightly specified sub-base material. Ballast is coarse angular stone for railway track beds and, confusingly, in UK merchant terms also a sand-and-gravel mix for concrete. Drainage aggregate is washed single-sized stone. Recycled aggregate is crushed concrete or demolition material.
This is the distinction that determines whether a job works. Graded aggregate contains a full spread of particle sizes down to dust. The fines fill the voids between larger stones, so when compacted the material interlocks into something close to a solid slab. That is exactly what you want under a driveway, patio or foundation.
Clean or washed aggregate has the fines screened out, leaving open voids between uniformly sized stones. Water moves through it freely, which is exactly what you want in a French drain, behind a retaining wall or around a perforated pipe — and exactly what you do not want as a load-bearing base, because with nothing filling the voids it never truly locks up.
Use graded for structure, clean for drainage. Reversing them produces either a base that keeps moving or a drain that silts up within a season.
Bulk density varies more across aggregate types than people expect. Recycled crushed concrete is light at around 81 pounds per cubic foot. Clean drainage stone sits near 95 because of its void space. General crushed stone is about 100, gravel 105, and dense graded base blends like MOT Type 1 and crusher run reach 131 to 135 — a range of more than 60 percent from lightest to heaviest.
That matters because a cubic yard of one material can weigh 1.10 tons and another 1.82. If you convert volume to weight with a single generic figure, as several calculators do, you can be a third out. Moisture adds another 10 to 25 percent for saturated material, which is why suppliers selling by weight usually weigh loads rather than applying a fixed conversion.
Loose aggregate delivered from a truck is full of voids. Rolling or plate-compacting it rearranges the particles into a tighter packing, and the material occupies noticeably less space — typically compacting to 80 to 90 percent of its loose volume. The practical consequence is that reaching a specified compacted depth requires more loose material than the design volume suggests.
How much more depends on the material. Clean single-sized drainage stone barely compacts at all, perhaps 5 percent, because there are no fines to migrate into voids. Dense graded blends compact hardest — MOT Type 1 can take 25 percent, crusher run around 20 to 22. This calculator applies a suggested factor per material and lets you override it.
It is worth being precise about terminology here, because published guidance is often sloppy. Compaction is a volume change inherent to the material. Waste is loss — spillage, over-excavation, material left in the barrow. Some calculators tell you to use the waste field to cover compaction, which works arithmetically but obscures what you are actually budgeting for and makes it impossible to adjust one without the other.
A base course spreads concentrated surface loads over a wider area of subgrade, so the soil beneath is never asked to carry more than it can. Depth follows the load and the subgrade: 4 inches under a patio, 6 to 8 under a residential driveway, 8 to 10 for parking, and 10 to 14 for industrial traffic. Soft or clay subgrades need more of everything.
Build in lifts. A plate compactor meaningfully influences only the top 4 to 6 inches, so a 12-inch base placed in one go leaves the bottom half loose, and it will settle later. Two or three compacted lifts take slightly longer and produce a base that lasts decades.
No amount of aggregate compensates for a bad subgrade. Strip topsoil and organic material, proof-roll the surface to find soft spots, and dig out and replace anything that pumps or deflects under load. Then lay geotextile fabric before placing stone.
That fabric is the cheapest insurance on any base job. Without it, aggregate gradually works down into the soil and soil migrates up into the aggregate, and within a year or two you have lost a meaningful share of the base depth you paid for. Woven fabric for load separation, non-woven where drainage is the priority.
Drainage wants the opposite of compaction: maximum void space for water to move through. Use washed, angular, single-sized stone — typically #57 or #2 — with the fines removed, wrapped in filter fabric to keep soil out.
A French drain is usually a trench 12 inches or deeper, lined with fabric, with a perforated pipe bedded in washed stone and the fabric folded over the top before backfilling. Behind a retaining wall, a full-height column of clean stone with a drain at the base relieves hydrostatic pressure, which is the single most common cause of retaining wall failure.
In concrete, aggregate is structural rather than filler. Coarse aggregate provides strength and dimensional stability while reducing the cement required; fine aggregate fills the spaces between. Gradation, cleanliness and particle shape all affect workability and final strength, and standards set limits on silt, clay and organic content because these interfere with the cement bond.
Typical nominal maximum size for slabs is three-quarter inch, reduced where reinforcement is closely spaced, since aggregate must pass freely between bars and around them to the formwork.
Road pavements are layered systems, each spreading load onto the one below: surface course, binder course, base and sub-base, over prepared subgrade. Sub-base is typically 8 to 12 inches of MOT Type 1 or an equivalent DOT-specified graded material, placed and compacted in lifts.
Transport department specifications define permitted gradation envelopes and required compaction, usually as a percentage of maximum dry density from a laboratory test. For anything carrying public or heavy traffic, that specification governs and this calculator is only a quantity estimator.
Under a concrete slab, 4 inches of clean crushed stone provides a level working platform, a capillary break stopping moisture rising, and drainage beneath the slab. Clean #57 stone is the usual choice because it does not need heavy compaction to be stable and it drains freely. A vapour barrier goes over the stone, directly beneath the concrete.
Crushed concrete and demolition material performs well for base course, fill and haul roads, at lower cost and with a considerably smaller carbon footprint than virgin quarried stone. It is lighter — around 81 pounds per cubic foot — so a cubic yard weighs less, which changes the volume-to-weight conversion noticeably.
Quality varies with the source. Well-processed recycled aggregate with contaminants removed is a genuinely good base material; poorly processed material with brick, timber or gypsum in it is not. Ask what it was made from, and check whether your specification permits it.
Give the supplier the loose volume including compaction, not the design volume. Tell them the application — they will often recommend a different grade and are usually right. Confirm whether the quote is per ton or per cubic yard, since the two are not directly comparable without the density.
Before the truck arrives, check overhead clearance for a raised bed, whether the standing ground is firm, and exactly where the pile should drop. Delivery is charged per trip, so an order that spills slightly into a second load is disproportionately expensive — worth checking whether a small design change brings you under.
Spread in lifts of 4 to 6 inches and compact each one before adding the next. A vibrating plate suits small areas and confined spaces; a roller is far more effective on driveways and larger pads. Slightly damp material compacts better than bone-dry or saturated, which is why roadworks are watered before rolling.
Check depth as you go with a stick cut to the target rather than by eye, and grade surfaces to shed water — an inch or two of fall or a slight crown prevents ponding that undermines the base from above.
Aggregate gradation, sampling and testing are covered by established standards, with sieve analysis and size designations defined by ASTM specifications in North America and by national standards elsewhere. State transport departments publish their own base course requirements, and industry bodies including the National Stone, Sand & Gravel Association publish guidance on properties and use.
For domestic projects these mostly matter as shared vocabulary — asking for "#57 washed" or "MOT Type 1" gets you a defined material anywhere in its market. For structural, highway or inspected work, the governing specification takes precedence over any general guidance, including this page.