Crushed Concrete Calculator

About the Crushed Concrete Calculator

Crushed concrete, also called recycled concrete aggregate or RCA, is made from old slabs, footings, sidewalks and roads that are broken up, run through a crusher and screened to size. Metal reinforcement is pulled out with magnets along the way. The result is an angular, grey aggregate that compacts well and is widely used for driveway bases, construction entrances, fill and drainage. Because it is a waste product, it is usually cheaper than freshly quarried stone, and using it keeps concrete out of landfill.

This crushed concrete calculator works out how many tons you need for an area, then compares the cost with virgin crushed stone for the same job. Crushed concrete is lighter than quarried rock, so the same volume takes fewer tons, which adds to the price advantage. Enter the area, depth and both prices to see the saving.

How to Use the Crushed Concrete Calculator

Enter the length and width in feet and the depth in inches.

Enter an allowance for compaction and waste, usually around 10%.

Enter the price per ton for crushed concrete and for virgin stone.

The Formulas

  cubic yards    = length × width × depth ÷ 12 ÷ 27 × (1 + allowance)
  recycled tons  = cubic yards × 1.2
  virgin tons    = cubic yards × 1.4
  saving         = virgin tons × virgin price − recycled tons × recycled price

Step-by-Step Example

A 40 × 12 ft driveway, 4 inches deep, 10% allowance, $20 against $35 a ton.

  volume    40 × 12 × 4 ÷ 12 ÷ 27 = 5.93 yd³ × 1.1 = 6.52 yd³
  recycled  6.52 × 1.2 = 7.82 tons × $20 = $156.44
  virgin    6.52 × 1.4 = 9.13 tons × $35 = $319.41
  saving    $162.96, about 51%

Why Crushed Concrete Is Lighter

Concrete is a mix of stone, sand and cement paste with tiny air pockets. Once it is crushed, each piece still contains some of that lighter paste, so a cubic yard of crushed concrete weighs about 1.1 to 1.3 tons, compared with about 1.35 to 1.5 tons for crushed limestone or granite. Since both are sold by the ton, a lighter material gives more volume per ton, and you need fewer tons to fill the same space. The calculator uses 1.2 tons per yard for crushed concrete and 1.4 for virgin stone.

Grades of Crushed Concrete

Recyclers sell several sizes. A product similar to crusher run, often 1½ inch or ¾ inch minus with fines, compacts into a firm base for driveways and slabs. Clean crushed concrete with the fines screened out drains well and can be used for drainage layers and backfill, though it is less stable on its own. Larger 2 to 4 inch pieces are used for construction entrances, where they knock mud off truck tyres, and for stabilising soft ground. Ask the yard which product suits your job.

Quality Matters

Material quality varies more than with quarried stone. Good crushed concrete is clean and consistent, free of rebar, wire mesh, wood, brick, plastic and asphalt. Poorly processed material can contain sharp steel and lumps that will not compact. Visit the yard and look at the pile if you can, or ask whether the product meets a state transportation department specification, which sets limits on contaminants and grading.

Environmental Considerations

Fresh crushed concrete contains free lime, so rainwater running through it is alkaline and can carry fine cement dust. That is harmless on most driveways, but avoid using it right beside streams, ponds, wetlands and wells, and in beds with acid-loving plants. Some states restrict its use near water. Over time the surfaces carbonate and the effect fades. Using recycled concrete instead of quarried stone saves landfill space and reduces quarrying and haulage, which is why many public road projects now require a share of recycled aggregate.

Re-Bonding

A useful quirk of crushed concrete is that leftover unhydrated cement can react with water and lightly bind the compacted layer together over the first months. This can make a driveway base firmer than the same thickness of stone, though it also makes it harder to rework later.

Preparing the Site

Crushed concrete is laid much like crusher run. Strip the topsoil and roots, compact the subsoil, and lay a geotextile on soft or wet ground so the aggregate is not pushed into the mud. Spread the material in lifts of about 4 inches loose, dampen it, and compact each lift with a plate compactor or roller. Crown or slope the surface so rain runs off rather than soaking in, and add edging where it borders lawn so the stone stays put.

Supply and Availability

Recycling yards are most common near cities, where demolition provides a steady supply. In rural areas crushed concrete can be scarce, and a long haul can wipe out the price advantage. Always compare the delivered cost, not just the price per ton, and ask how much stock the yard holds if you need a large quantity.

Understanding Your Result

The headline gives the tons of crushed concrete.

The volume line shows the cubic yards with your allowance.

The cost comparison line prices both materials.

The saving line shows the difference in dollars and percent.

When Should You Use This Calculator?

Use it when pricing a driveway, parking pad or shed base.

Use it to decide whether recycled aggregate is worth the trip to a recycling yard.

Use it to check how much a lighter material reduces the tonnage you order.

Common Mistakes

Using stone densities for crushed concrete. It is lighter, so fewer tons are needed.

Buying unscreened material. Rebar and debris make a poor base.

Using it next to water. Alkaline runoff can harm streams and ponds.

Skipping compaction. Like crusher run, it needs to be compacted in lifts.