Concrete Pricing Guide: Cubic Yards In, Square Feet Out

Short answer: A concrete pricing guide has to carry two units at once. Cubic yards buy the mix — area in square feet times thickness in feet, divided by 27, which is square feet divided by 81 for a 4 in slab. Square feet sell the job. Between them sit excavation, base stone, forms by the linear foot, steel, finish, saw joints by the linear foot, and cure. The same 600 sq ft driveway below is 8 yards on both lots and 38 crew-hours on one, 85 on the other.

Concrete is the one trade where the thing you order and the thing you sell are measured in different dimensions. The plant bills you by volume. The homeowner thinks in surface. Everything that decides whether the job made money — the dirt, the base, the forms, the steel, the access, the weather — sits in the gap between those two numbers and shows up on neither. This page walks that gap. The deduction side of the same truck is in concrete business expenses.

Which unit does the customer buy, and which one do I buy?

The customer buys square feet of finished surface. You buy cubic yards of ready-mix, tons of stone, linear feet of form lumber, and hours.

That mismatch is not a nuisance to be smoothed over. It is the whole reason a per-square-foot concrete price means so little on its own. Two slabs of identical area can differ by 50 percent in volume because one is 4 in and the other is 6 in with a thickened edge. Two slabs of identical volume can differ by twice the labor because one is a rectangle a truck can reach and the other is behind a house.

Footings and walls make the mismatch obvious, because they have no meaningful surface number at all. A footing is width times depth times length, straight to yards. Nobody quotes a footing per square foot, and the only reason flatwork gets quoted that way is that it is the number a homeowner can compare.

How do I turn a slab into cubic yards without shorting the truck?

One formula, then a deliberate over-order.

Cubic yards = area in ft² × thickness in ft ÷ 27.

Slab thickness	Divide square feet by	600 sq ft becomes
4 in	81	7.41 yd³
5 in	64.8	9.26 yd³
6 in	54	11.11 yd³
8 in	40.5	14.81 yd³

Then add 5 to 10 percent. A subgrade that dips half an inch across a 600 sq ft pad has already swallowed a quarter yard, and formwork that bellies out at midspan swallows more. On a 7.41 yd³ slab you order 8.

Running short is not a rounding error, it is a defect. A second truck means a cold joint where the first load set, an extra delivery charge, and a crew standing in the sun on your clock. Running a quarter yard over means one wheelbarrow of waste. The asymmetry is not close.

Thickened edges get calculated separately and added: a 12 in wide by 12 in deep turndown around a 100 ft perimeter is 100 cu ft, which is another 3.7 yd³ on its own.

What does the mix itself cost before anyone touches it?

More lines than the per-yard number on the plant’s quote sheet.

• Strength. 3,000, 3,500, and 4,000 psi are different per-yard prices. Exterior flatwork in a freeze-thaw region also needs air entrainment, which is another line.
• Fiber or admixtures. Synthetic fiber, a water reducer, a non-chloride accelerator in cold weather, a retarder in heat — each is priced per yard and each has to be ordered when you place the load, not when the truck arrives.
• Short-load fee. Below the plant’s minimum, typically somewhere near a full truck, you pay a surcharge per yard short. Two small pours on two days can cost more in short-load fees than the concrete.
• Unload time. Plants allow a free unload window, commonly a handful of minutes per yard, then bill standby by the minute. An 8 yard load might give you under an hour before the meter starts.
• Saturday, after-hours, and environmental or fuel surcharges. Read the rate sheet, not the headline price.
• Pumping. A line pump or a boom pump is its own invoice with a setup fee and a minimum, and you lose close to a yard priming the line and washing out.

What happens before the truck shows up?

Most of the job, and none of it is concrete.

Excavation. Cut depth is slab plus base. For a 4 in slab on 4 in of stone, that is 8 in over the whole footprint: 600 × 0.667 ÷ 27 = 14.8 yd³ in place, which swells by roughly a fifth once it is loose. That is two trailer loads of spoil to move and tip before anything else happens.

Base and compaction. Crushed stone at 4 in uses the same ÷81 math — 7.41 yd³ — then converts to tons at your quarry’s density, commonly somewhere around 1.3 to 1.5 tons per yard. Compact it in lifts. An uncompacted base is a callback with your name on it.

Forms. Linear feet of perimeter, in 2x lumber, with stakes at roughly 4 ft on center. A 20 by 30 pad is 100 linear feet of form and about 25 stakes before corners and bracing. Form lumber is partly consumable, partly reusable, and radiused work is neither.

Steel. Wire mesh comes in 5 by 10 sheets covering 50 sq ft each, and laps eat about 15 percent, so 600 sq ft takes roughly 14 sheets. Rebar is counted in sticks: #4 at 18 in on center each way over 20 by 30 works out to about 840 linear feet, which is 42 sticks of 20 ft, plus chairs and tie wire.

Vapor barrier under interior slabs, by the roll, with taped seams.

What does the finish add on top of the flatwork?

The finish is a separate product sold over the same square feet.

A broom finish is the baseline: float, edge, joint, broom, done. A hard steel trowel finish for a garage takes more passes and a tighter window, and in a closed building it means a power trowel and the fuel or power to run it. Exposed aggregate adds a surface retarder and a wash-off step, plus containment for the slurry.

Stamped work is a different job wearing the same square footage. It adds dry-shake color hardener at the manufacturer’s published rate, commonly in the neighborhood of 60 lb per 100 sq ft for standard coverage, plus release agent, plus mats you either own or rent, plus a crew large enough to stamp the whole pour inside the set window, plus a sealer that will need reapplying. Integral color is priced by the yard at the plant instead, and the two approaches do not cost the same.

Where do saw joints, cure, and weather land in the price?

All three are linear-foot or per-day lines, and all three get skipped.

Control joints run in linear feet. Cut depth is about a quarter of the slab thickness — 1 in on a 4 in slab — and panel spacing in feet runs roughly two to three times the slab thickness in inches, so a 4 in slab wants panels around 8 to 12 ft. A 20 by 30 pad on a 10 ft grid takes one 30 ft cut and two 20 ft cuts: 70 linear feet of sawing, on a clock that starts hours after the finish and does not wait for your schedule.

Dry-cutting concrete generates respirable crystalline silica, and OSHA’s construction silica standard sets out the controls for walk-behind saws in Table 1 of 29 CFR 1926.1153. Water on the blade is a real consumable and a real setup, not an optional nicety.

Curing is cure-and-seal by the gallon at roughly 200 to 300 sq ft per gallon, or blankets and plastic rented by the day.

Weather changes the mix ticket and the labor. Hot, dry, windy conditions mean an early start, evaporation retardant, a retarder in the load, and more finishers to keep up with a set that is running away. Cold means an accelerator, heated water at the plant, insulated blankets left on for days, and a pour that cannot happen at all below the temperature your local code allows.

What does the same 600 sq ft driveway cost on two lots?

A 20 by 30 driveway, 4 in of 4,000 psi over 4 in of compacted base, wire mesh, broom finish, jointed on a 10 ft grid. Eight yards ordered on both.

Lot A — a 2019 subdivision. Flat, open, virgin ground, the truck backs to the forms and the chute reaches every corner.

Lot B — a 1948 house. An existing 4 in slab to break out, a gate the truck cannot pass, 140 ft from the street to the pad, 3 ft of fall requiring a swale, tree roots in the cut, and a July pour date.

Operation	Lot A	Lot B
Layout, strings, grade check	1.5 hr	3.0 hr
Break out and haul old slab	—	16.0 hr, ~15 tons tipped
Excavate and haul spoil	6.0 hr, 2 loads	11.0 hr, roots by hand
Base stone placed and compacted	4.0 hr, machine spread	10.0 hr, carried through the gate
Forms and stakes	4.5 hr, 100 lf	7.5 hr, stepped plus swale
Mesh, chairs, tie	3.0 hr, 14 sheets	3.5 hr
Pour and finish	15.0 hr, chute	20.0 hr, line pump, 5:30 start
Pump setup, prime, wash out	—	3.0 hr plus pump invoice
Saw joints	1.5 hr, 70 lf	2.5 hr, 70 lf plus swale
Strip forms, cure and seal, clean	3.0 hr	5.0 hr
Crew hours	38.5	81.5
Ready-mix ordered	8 yd³	8 yd³

The concrete line is identical. Everything that decides the outcome is not. And the wheelbarrow arithmetic on Lot B is the reason the pump is not optional: a 6 cu ft contractor barrow is 0.22 yd³, so 8 yards is 36 round trips of 280 ft each — nearly two miles of pushing 300 lb, inside a free unload window that runs under an hour.

What is a published per-square-foot concrete price worth?

It is a mirror, not a ruler. Use it after you have built your own number, to see whether you are wildly out of step with the market you actually work in. Ready-mix pricing, tipping fees, quarry distance, labor cost, and the length of the pour season vary enough between regions that a single national figure is close to meaningless on your street.

Build the number from the bottom instead: material at your real cost, crew hours at your loaded rate, overhead per hour from your own annual figures, then profit.

And keep markup and margin apart, because on a pour they get confused constantly. Markup sits on top of cost; margin comes out of price. A pour that costs you $4,300 with a 25 percent markup invoices at $5,375, and your margin is 20 percent. If you wanted 25 percent margin, the arithmetic is $4,300 ÷ 0.75 = $5,733. Marking up the mix ticket alone is worse still — the mix is often less than a fifth of what the job costs you, so a fat markup on that one line moves almost nothing.

What has to get written down on pour day?

The paperwork that decides whether a crack argument two winters from now goes your way.

Keep the delivery tickets. Every one of them, with the mix design, the yards, the water added on site, and the time stamps. Photograph the compacted base before the steel goes in, the steel before the pour, the joints after they are cut, and the finish the day you strip. Note the air temperature and the start time. Log the tipping ticket from the old slab by weight.

That trail also has to become an invoice while the customer is still happy. Keel is built for exactly that: it runs entirely on the phone, with no account, no login, and no bank connection, and the App Store privacy label reads Data Not Collected. Photograph the plant ticket and the transfer station receipt on the spot — they are read on-device with Apple Intelligence — log the runs to the quarry and back for mileage, then send the invoice from the truck with your logo and a payment QR on it. The free tier is unlimited invoices, receipts, and mileage, and Keel Pro is a one-time $249.99 Lifetime purchase rather than a subscription. Getting the money in after that is covered in how to get clients to pay, and the year-end filing pile is in contractor receipt organizer.

Frequently asked questions

How many cubic yards of concrete do I need for a slab?

Multiply the area in square feet by the thickness in feet and divide by 27. For a 4 in slab, that shortcut is square feet divided by 81, so 600 sq ft needs 7.41 yards. Order 5 to 10 percent over for subgrade dips and form belly, and calculate any thickened edge or turndown separately and add it.

Should I quote concrete per square foot or per cubic yard?

Quote the customer per square foot for flatwork, because that is what they can compare, and per cubic yard for footings and walls where there is no meaningful surface. Build both numbers from the same place: yards of mix, tons of base, linear feet of form and joint, and crew hours at your loaded cost.

Why does a driveway cost more than a patio of the same size?

Thickness and steel, mostly. A driveway carrying vehicles is usually thicker than a patio, often with heavier reinforcement and a thickened edge, so the same footprint buys more yards. Access differs too — patios are frequently in back yards where the chute cannot reach, which adds a pump or a buggy line.

What is a short-load fee on ready-mix?

A surcharge the plant adds when your order falls below their minimum load, charged per yard short. It exists because sending a truck out half full costs them nearly what a full one does. Combining two small pours onto one delivery, or scheduling them the same morning, is often the cheapest fix.

How far apart should control joints be in a 4 inch slab?

Panel spacing in feet runs roughly two to three times the slab thickness in inches, so a 4 in slab wants joints somewhere around 8 to 12 ft, kept as close to square panels as the shape allows. Cut about a quarter of the slab depth, and cut early — the window opens within hours of the finish.

Does the weather really change what I should charge?

Yes, and on two lines. The mix ticket changes, because heat calls for a retarder and evaporation control while cold calls for an accelerator and heated water. The labor changes more: a hot pour needs an earlier start and more finishers, and a cold pour needs blankets left in place for days before forms come off.

---

This article is general information, not professional or tax advice.