Estimate Demolition Volume Before Breaking Concrete
Use this Concrete Demolition Calculator to estimate concrete volume, approximate demolition weight, broken-debris volume, haul loads and optional removal cost for slabs, patios, driveways, sidewalks, walls and foundation sections. Enter actual project dimensions, concrete density, debris swell factor and hauling capacity to build a practical demolition takeoff.
Estimate a slab, wall or foundation section, convert known debris into haul loads, or model demolition and disposal cost.
Estimate intact slab volume, approximate weight and loose broken-debris volume.
Editable planning density
1.35 means loose debris volume = 135% of intact volume
Planning estimate only. Reinforcing steel, embedded items, thickened edges, hidden footings, variable slab thickness and base material can materially change demolition weight and disposal quantity.
Estimate removal volume and weight for a uniform concrete wall or foundation section.
Structural walls require project-specific demolition planning. This tool estimates quantity only and does not determine bracing, sequencing, temporary support or safe demolition method.
Convert total demolition weight and loose volume into weight-limited and volume-limited haul loads.
Use legal/supplier-confirmed payload
Use actual container or truck body capacity
Build a simple demolition subtotal using area, removal rate, tonnage, disposal and haul charges.
Cost model only. Utility locating, permits, saw cutting, reinforcement, equipment mobilization, dust controls, shoring, hazardous materials, traffic control, restoration, taxes and contractor overhead may require separate pricing.
A Concrete Demolition Calculator starts with the intact geometry of the concrete. For a slab, length is multiplied by width and thickness. For a wall, net wall area is multiplied by wall thickness. These dimensions create cubic feet, which are divided by 27 to produce cubic yards.
Weight is estimated by multiplying intact cubic feet by the concrete density entered by the user. The calculator defaults to 145 pounds per cubic foot as a planning value, but it is editable because actual concrete density can vary. Reinforcement, embedded steel and attached materials can add weight that is not represented by concrete density alone.
Broken concrete also occupies more loose space than the intact slab or wall. The debris-swell factor multiplies the intact volume to create an estimated loose volume. A factor of 1.35, for example, means the loose broken material is modeled as 135% of the original intact volume. The correct factor depends on breaker size, fragment size, loading method and how densely the material packs in the container.
Thickness is converted from inches to feet.
Use a project-specific density when known.
The swell factor is a planning input, not a universal constant.
Estimate patios, sidewalks, driveways, floors and concrete pads from dimensions.
Estimate uniform concrete walls and foundation sections after subtracting openings.
Compare weight-limited and volume-limited loads to find the controlling haul count.
Combine removal, disposal, hauling and other fixed project costs.
Consider a 20 ft × 20 ft concrete slab that is 4 inches thick. The slab area is 400 square feet. Four inches equals one-third of a foot, so the concrete volume is approximately 133.33 cubic feet, or 4.94 cubic yards.
At an entered planning density of 145 lb/ft³, the concrete weighs approximately 19,333 pounds, or 9.67 short tons. If a 1.35 loose-debris swell factor is used, the broken debris volume is approximately 6.67 loose cubic yards before any additional quantity allowance.
The density field is editable because not every concrete element has the same unit weight. Normal-weight concrete is commonly much heavier than lightweight systems, and some structures include dense aggregate or significant reinforcement. The calculator estimates the concrete portion only from the density entered.
Rebar, welded wire reinforcement, post-tensioning, steel embeds, anchor plates, curbs, masonry and asphalt overlays can add mass or complicate handling. Reinforced concrete may also produce larger interconnected pieces until the steel is cut, making the loose packing behavior different from plain unreinforced concrete.
If demolition drawings or prior construction records show thickened edges, grade beams, column pads or footings below the slab, calculate those elements separately and add them to the flat slab quantity.
Measure the actual area scheduled for removal rather than the entire property or building footprint. For irregular concrete, split the area into rectangles or other measurable shapes. Thickness is often the most uncertain input, so confirm it through drawings, exposed edges, cores or other appropriate field investigation where needed.
Mark exactly which concrete will be demolished.
Calculate square footage from actual removal dimensions.
Check drawings or field conditions instead of assuming a uniform slab.
Plan for rebar, mesh, dowels or post-tensioning where present.
Match debris weight and loose volume to legal and supplier limits.
When concrete is intact, almost all of its volume is solid material. Once it is fractured, voids form between the broken pieces. This increases the space occupied by the debris even though the mass of the concrete has not increased. The calculator calls this the swell or bulking factor.
Small well-graded fragments can pack more tightly than large irregular chunks. Concrete with rebar may bridge across voids and occupy even more space until reinforcement is processed. Loading with an excavator bucket, skid steer or by hand can also change packing. Use the calculator's editable factor as a planning tool and compare it with local hauling experience.
The haul-load calculator compares two constraints: weight and volume. If 20 tons of debris must be removed and a hauler permits 10 tons per load, at least two loads are required by weight. If the same debris occupies 30 loose cubic yards and the container is rated for 10 cubic yards, at least three loads are required by volume. The controlling estimate is three.
Actual hauling must comply with legal axle and gross vehicle limits, container limits, road restrictions and the hauler's contract. Dense concrete debris can exceed a container's allowed weight while leaving substantial empty physical space. Confirm acceptable loading practices before filling any roll-off or dump container.
A demolition quote can include much more than breaking concrete. The cost calculator separates a removal rate per square foot from disposal cost per ton, haul charge per load and other fixed cost. This makes it easier to enter a local contractor or recycling-yard quote without relying on a national average.
Demolition work can involve structural instability, stored energy, falling material, utilities and heavy equipment. For building or structural demolition, OSHA's demolition rules include preparatory requirements before employees begin work. Quantity math does not replace these requirements.
OSHA 29 CFR 1926 Subpart T addresses demolition operations. Section 1926.850 requires an engineering survey by a competent person before demolition begins to determine the condition of framing, floors and walls and the possibility of unplanned collapse. The same section also addresses control of electric, gas, water and other service lines before demolition work starts.
For structural walls and floor systems, sequencing and temporary support can be critical. Do not use the wall calculator to determine whether a wall is safe to remove.
Breaking, chipping, sawing, grinding and crushing concrete can generate respirable crystalline silica. OSHA's construction silica standard requires covered employers to limit worker exposure and use required controls. OSHA also provides specified control methods for many common construction tasks.
The calculator does not estimate dust-control equipment, water use, vacuum capacity or respiratory protection. Those are safety and compliance issues that should be planned for the actual demolition method and work environment.
Concrete from demolition may be accepted by local recycling facilities for processing into recycled aggregate or other uses, depending on contamination, reinforcement, local markets and facility rules. Recycling requirements vary by location, so contact the receiving facility before demolition and ask about accepted materials, rebar, soil contamination and tipping procedures.
The U.S. Environmental Protection Agency encourages reduction, reuse and recycling of construction and demolition materials where practical. Concrete recycling can reduce disposal volume, but the available option depends on local facilities and project specifications.
The weight stays approximately the same, but broken pieces occupy more space and create a separate hauling constraint.
Common questions about concrete removal volume, weight, dumpsters, hauling, disposal and demolition planning.