Concrete Driveway Cost Calculator

Reading the numbers

The default slab here is 40 by 16 feet at 4 inches thick. That is 640 square feet, which works out to 7.90 cubic yards of concrete before waste and 8.69 cubic yards with the standard 10% allowance. At $155 per yard delivered, the material comes to about $1,347.

Then the part that surprises most people: labour and preparation, set here at 150% of material, adds $2,021. Total roughly $3,368, or about $5.26 per square foot. The concrete itself is only about 40% of the job.

That ratio is the single most useful thing to take away. Homeowners spend their time shopping the price per yard — a $20 difference between suppliers, which is about $174 on this job — while the forming, grading, reinforcement and finishing that surround it account for the majority of the cost and vary far more between contractors.

Thickness is the decision you cannot undo

Going from 4 to 6 inches raises the material by half and the total by about $1,684 on this slab. Against a job that costs several thousand dollars and is expected to last decades, that is inexpensive insurance — and it is the option you lose forever once the truck arrives.

Choose 5 or 6 inches if a delivery truck, moving van, RV or boat will ever sit on it, if the soil is poorly compacted, or if the slab runs over a utility trench. Four inches is genuinely fine for two cars and nothing heavier.

• 4 inches — 8.69 cubic yards, about $3,368 total, $5.26 per square foot. Suitable for passenger cars.
• 5 inches — 10.86 cubic yards, about $4,210 total, $6.58 per square foot. Light trucks and SUVs.
• 6 inches — 13.04 cubic yards, about $5,052 total, $7.89 per square foot. RVs, heavy vehicles, or soft soil.

Why the waste factor is not optional

The 10% allowance exists because the real world is not a rectangular prism. Subgrade is never perfectly level, forms bow outward under pressure, some material spills during placement, and over-excavated areas get filled with concrete rather than dirt.

Turning it down to zero saves 0.79 cubic yards on this slab — about $122 of material. That is a bad trade. Coming up short means the truck leaves, the pour stops mid-way, and you pay a second short-load delivery fee to finish. Worse, the joint where the second pour meets the first is a cold joint: a visible seam and a structural weak point that will crack before the rest of the slab.

Complex shapes, steep slopes or a badly prepared base can justify 15% or more. Ten percent is the standard for a straightforward rectangle on a prepared base.

The short-load fee that catches small jobs

Ready-mix suppliers charge a fee — often $60 to $300 — for loads below a threshold, typically around 4 cubic yards, because a truck costs roughly the same to send whether it carries 2 yards or 10. This calculator does not add that fee, so small jobs will cost more in reality than the estimate shows.

A 20 by 10 foot slab at 4 inches needs 2.72 cubic yards: about $421 of material and roughly $1,052 all in. Add a short-load fee and the economics shift enough that bagged concrete becomes competitive. Below about 1 cubic yard, bags usually win outright.

If your job lands between 2 and 4 yards, ask the supplier for the exact short-load fee before deciding. Sometimes ordering slightly more than you need is cheaper than ordering exactly what you need.

Bags or ready-mix?

The bag count is there for people mixing by hand, and the default slab is a useful illustration of why that is usually the wrong choice at this size. It takes 392 bags of 80 lb mix to pour 8.69 cubic yards. At a typical retail price that is more expensive than the delivered concrete, and it involves moving about 31,000 pounds of material by wheelbarrow.

More importantly, hand-mixing a slab this size means placing concrete over hours rather than minutes, which is exactly how cold joints and inconsistent finishing happen. A driveway wants to be poured in one continuous operation.

Bags make sense for small repairs, walkways, footings and anything under roughly a cubic yard — including the awkward situation where you need 1.5 yards and the short-load fee makes delivery uneconomic. Switch the bag size above to see the difference: the same slab needs 522 bags of 60 lb mix instead of 392 of 80 lb.

What drives the labour line

If the subgrade is not compacted properly, no amount of concrete thickness or reinforcement will save the slab. It is the single most common cause of a driveway that cracks and settles within a few years, and it is invisible once the pour is finished — which is why it is worth being on site for that stage specifically.

What is inside that number

• Demolition and hauling of an existing surface, which can be a substantial line on its own.
• Excavation, grading and compacting the subgrade — the least visible and most consequential part of the job.
• Formwork, and the labour to set it level and brace it properly.
• Reinforcement: wire mesh or rebar.
• Finishing — broom, trowel, exposed aggregate or stamped — which ranges from quick to highly skilled.
• Curing and sealing.

What this estimate leaves out

A plain broom-finished slab in most US markets lands between about $5 and $10 per square foot installed. The default here produces $5.26, which sits at the low end of that range — appropriate for a simple rectangular pour on a prepared base, and optimistic if your site needs work.

• Removal and disposal of an existing driveway — often $1,000 to $3,000 depending on size and material.
• Drainage work, including any regrading needed to move water away from the house.
• Permits and inspection fees, which vary widely by jurisdiction.
• Base material — compacted gravel — if the existing subgrade is inadequate.
• Decorative treatments. Stamping, colour and exposed aggregate typically push the installed cost into the $12 to $18 per square foot range.
• Sealing, which is usually recommended after the first year and periodically thereafter.
• Any reinforcement beyond basic mesh, and control joints cut after the pour.