Cement Pad Cost Calculator

What a cement pad is and what drives the price

A cement pad is a flat slab of concrete poured on the ground to hold something: an air conditioning condenser, a generator, a hot tub, a shed or a trailer. The material people call cement is concrete, a mix of Portland cement, water, sand and crushed stone, and ready-mix arrives in a truck.

The National Ready Mixed Concrete Association describes each batch as made for the job and delivered fresh, and the Portland Cement Association notes the same thing: ready-mix is tailor-made for the specifications and delivered so it can be placed and finished on site.

Four numbers set the cost of almost every pad: the area in square feet, the thickness in inches, the price per cubic yard of concrete, and the labor rate per square foot. The gravel base, the reinforcement and the minimum delivery follow from those four.

Working out the volume of concrete

Concrete is sold by the cubic yard, and one cubic yard is 27 cubic feet, so the first step is turning pad dimensions into yards. Multiply length by width for the area in square feet, multiply by the thickness in inches divided by 12 for the depth, then divide by 27.

For a 10 by 10 foot pad 4 inches thick that reads 10 x 10 x 4 / 12 / 27 = 1.23 cubic yards. A 12 by 16 foot patio of the same thickness needs 12 x 16 x 4 / 12 / 27 = 2.37 cubic yards. A 6 by 6 foot pad 5 inches thick needs 6 x 6 x 5 / 12 / 27 = 0.56 cubic yards.

You never order the exact figure. Add 10 percent for waste and round up to what the plant can deliver. A 10 by 10 foot pad becomes 1.23 x 1.10 = 1.35 cubic yards, so most trucks bring at least 1.5 yards for a job this size. Small pads also carry a minimum load charge, because the truck comes out whether it is full or not.

Worked example: a 10 by 10 foot equipment pad

Take a 10 by 10 foot pad for a generator, 4 inches thick, with a 4 inch compacted gravel base and welded wire mesh. Concrete runs 140 dollars a cubic yard, the gravel 45 a cubic yard, the mesh 0.60 dollars a square foot and labor 6 dollars a square foot.

The concrete is 10 x 10 x 4 / 12 / 27 = 1.23 cubic yards, which with the waste allowance rounds up to 1.50 yards ordered, so 1.50 x 140 = 210 dollars. The base covers the same footprint at 4 inches, so it also comes to 1.50 yards, giving 1.50 x 45 = 67.50 dollars of gravel. The mesh covers the whole surface: 10 x 10 = 100 square feet at 0.60 dollars is 60 dollars. Labor at 100 x 6 = 600 dollars finishes the job.

That is the whole logic: geometry gives you the yards, the yards give you the material cost, the square footage gives you the reinforcement and labor, and the sum is a number you can hold a contractor to.

Concrete price per cubic yard and the delivery minimum

Delivered ready-mix in most US markets runs 125 to 150 dollars a cubic yard, and that number moves with fuel prices, cement prices and the distance from the plant. A 1.5 cubic yard order at 140 dollars is 210 dollars of concrete, which sounds cheap until you remember the truck still has to come out and pump it in.

Small pads hit the delivery minimum hard. A truck that delivers a yard and a half costs the plant the same as one that delivers ten yards, so the plant either charges a short-load fee or prices small orders higher. Bagged concrete is an option for very small pads and the only route when a truck cannot reach the spot. An 80 pound bag yields 0.60 cubic feet, so the 10 by 10 foot pad needs 33.33 / 0.60 = 55.55, which means 56 bags, or 62 with the waste allowance, and at 5.50 dollars a bag that is 341 dollars to your driveway.

Check the delivery radius before you commit. A plant 60 miles away may charge more per yard than one 15 miles away, and on 1.5 yards that can beat any labor negotiation.

Gravel base and reinforcement

The base does more work than most people expect. Concrete is strong in compression but weak in tension, so a slab sitting directly on soil can crack the moment the ground moves. A layer of compacted crushed gravel, usually 4 inches, spreads the load, drains water away and gives the slab a stable seat.

Reinforcement handles the other half. Welded wire mesh at 0.60 dollars a square foot works fine for light equipment. A rebar grid on 18 inch centers costs about 1.50 dollars a square foot and is worth it under a hot tub, a heavy generator or anything that rolls. Fiber mesh mixed into the concrete stops surface cracking only, not cracking through the slab.

Four inches of base on a 10 by 10 foot pad adds 1.23 cubic yards of gravel before waste, so 67.50 dollars at 45 a yard. That is cheap insurance against a cracked slab.

Labor, and what the per square foot rate covers

Labor runs 4 to 8 dollars a square foot for a plain broom finish on a flat, accessible site. That covers the crew's time to set forms, place the gravel, set the vapor barrier and mesh, pour and screed the concrete, cut control joints, float the surface, pull the forms and clean up. It does not cover demolition, hauling spoil, or a site where the truck cannot park next to the pad.

Labor surprises people on small jobs. On the 10 by 10 foot pad above, labor is 600 dollars out of a 937.50 dollar estimate. On a 12 by 16 foot patio the same crew and call-out spread over 192 square feet, so the per square foot rate falls even though the total rises.

Stamped, colored and exposed aggregate finishes sit on top of the base rate, and so do special jobs: a thickened edge, a slope for drainage, a drain line cutout or a night pour. Ask for the finish and extras as separate line items.

What a pad costs at common sizes

Here is what the same assumptions produce for the sizes people ask about most: concrete at 140 dollars a cubic yard, gravel at 45 a cubic yard, a 4 inch base, wire mesh at 0.60 dollars a square foot and labor at 6 dollars a square foot. Each pad carries at least one cubic yard, so the small ones pay the delivery minimum.

Notice what the table shows. The 4 by 6 foot pad comes to 320.90 dollars, less in total than the 10 by 10 foot pad, yet it works out at 13.37 dollars a square foot against 9.38 dollars. The fixed cost of the truck and crew is the same either way, so it gets spread over whatever space you have.

Thickness works the same way. On a 10 by 10 foot pad, going from 4 inches to 5 inches moves the ordered concrete from 1.50 to 2.00 cubic yards and adds 70 dollars. Going to 6 inches takes it to 2.50 yards and adds 140 dollars. Pads for people and light equipment are fine at 4 inches, a trailer pad needs more.

Getting a quote you can compare

Ask each contractor for the same five numbers in the same order: the total price, the price per square foot, the thickness, the volume of concrete in yards, and what the labor rate covers. The gap between two quotes written this way is a real gap in scope.

Check three things before you sign. That the concrete volume matches the geometry of your pad, easy to verify with the numbers above. That the reinforcement is named, mesh or rebar. And that the base is in the price, because a quote with no gravel base is not a better price, it is a slab that cracks.

One safety note for anyone cutting or breaking concrete. Sawing, grinding or crushing concrete and masonry releases respirable crystalline silica, and the OSHA construction standard for crystalline silica sets an exposure limit of 50 micrograms per cubic meter over an 8 hour shift. Wet the saw blade and use a HEPA vacuum.