How much concrete for a 12x16 patio?
2.4 cu yd of concrete for a 12x16 patio, at the settings most people start with. Below the calculator are the same numbers for the alternatives you are likely to choose, and what each one does to the total.
Reviewed · Method: measured dimensions, industry coverage rates, rounded up to real package sizes · How the numbers are calculated
Values are pre-filled for this page. Change anything and hit Recalculate.
The answer, and what it is made of
A 16 x 12 ft slab at 4 in thick is 2.4 cu yd of concrete. That is 113 bags at 80 lb each, which is why this size usually goes ready-mix: 113 bags is a long day with a mixer, and the truck arrives at a consistent slump instead of however you happened to mix the fortieth bag.
Planning figure for everything on that list: $841 to $1,336, with $1,053 as the realistic middle for the products most people actually buy. These are estimates for budgeting, not quotes. Prices move by region and by season, and the middle figure assumes a mid-range product rather than the cheapest thing on the shelf.
Thickness is the expensive variable: 2.4 cu yd at 4 in becomes 3.6 cu yd at 6 in, a jump of 50%. That extra concrete does less for crack resistance than a properly compacted base, which costs a fraction as much.
What changes if you change one thing
| Change the slab thickness | You buy |
|---|---|
| 4 in slab, foot traffic | 2.4 cu yd |
| 5 in slab, patio table and fire pit | 3 cu yd |
| 6 in slab, hot tub | 3.6 cu yd |
Every row is a live calculation, not an estimate. The shaded row is what this page defaults to.
What goes in the cart
| Item | Quantity |
|---|---|
| Concrete mix, 80 lb | 113 bags |
| Concrete mix, 60 lb (alternative) | 150 bags |
| Crushed gravel base | 3.3 tons (64 cu ft) |
| 6 mil vapor barrier | 192 sq ft |
| Form boards + stakes | 56 ft |
| Control joints | 2 runs |
Above 1 cubic yard, call the truck. 113 bags is 9,040 lb to haul and mix before it sets. A short-load fee beats a failed pour.
What this size actually changes
Two and a half yards is below the minimum load at most ready-mix plants, which typically charge a short-load fee under 3 yards. In practice that means a 12x16 patio at 2.4 yards and the same patio at 3 yards cost almost the same, so the sensible move is to pour it 5 in thick and take the extra concrete rather than pay for concrete you did not receive.
Figure. 12x16 patio at 4 in thick over a compacted base. Thickness sets the volume; the base sets whether it cracks.
How the quantity is worked out
Concrete is ordered by the cubic yard and sold in bags by weight, and the gap between those two units is where most estimates go wrong. A yard is 27 cubic feet, so a 10x12 slab at 4 in thick is 40 cu ft, or 1.5 cu yd. Rounded to whole yards at the ready-mix plant, that is 1.5 or 2 — and the shortfall shows up as a slab that is an inch thin at one corner.
Thickness is the expensive variable. Going from 4 in to 5 in on the same footprint adds 25 percent to the volume and 25 percent to the bill. Depth of the compacted base is the cheap variable: a proper 4 to 6 in base costs far less than an extra inch of concrete and prevents most of the cracking that a thicker slab would not have fixed anyway.
How to measure this job
Measure the patio footprint, then decide whether it meets the house or stands free. A patio against the house needs the slab set below the damp course and sloped away from the wall. A freestanding patio has its own edges to form, and those edges are where the concrete goes further than you expect.
Mark the outline with string and check the diagonals are equal before you dig. In a rectangular patio, equal diagonals mean square corners. If they differ by more than half an inch, the formwork is out and every subsequent step inherits the error.
Mistakes that cost real money
Ordering exactly the calculated volume
Ready-mix is delivered in whole yards and you cannot add half a yard on site. Order 5 to 10 percent over, because spillage, an uneven subgrade and a slightly deeper edge all consume concrete. Running short mid-pour produces a cold joint, which is a permanent weak line.
Sloping the patio toward the house
Water against the foundation is the most expensive mistake in this list. The slab must fall away from the wall at about 1/8 in per foot, and the finished level must sit below the damp course. Check with a level on the formwork before the pour.
Forming the patio tight to the house without a slip joint
A patio cast against the house wall needs a isolation joint where it meets the foundation, or the slab will crack along that line as the two structures move differently. A 1/2 in closed-cell foam strip does the job and costs nothing.
Trowelling the surface to a polish
A burnished patio is dangerously slick when wet, and outdoors it will be wet. Finish with a broom dragged across the surface, or a light salt finish. A steel-trowelled outdoor slab is a slip hazard, not a premium detail.
Frequently asked questions
How many 80 lb bags of concrete make a yard?
Forty-five. An 80 lb bag yields about 0.6 cu ft, and a cubic yard is 27 cu ft. That means a 1.5 cu yd slab needs roughly 68 bags, which is why anything past about one yard usually goes ready-mix: 68 bags is a long day with a mixer and a lot of lifting.
How much concrete for a 12x16 patio?
At 4 in thick, 2.4 cubic yards; at 5 in, 3.0; at 6 in, 3.6. Most suppliers have a minimum load, so a small patio often costs about the same at 2.4 yards as at 3 — order the thicker slab if the price is the same.
How much concrete for a 12x16 patio?
2.4 cubic yards at 4 in, 3.0 at 5 in, 3.6 at 6 in. Because of short-load fees, the 5 in version often costs the same as the 4 in one — ask before you decide.
Do I need rebar in a patio slab?
Not usually for foot traffic. Wire mesh or fibres control shrinkage cracks, which is the main risk on a slab on grade. Rebar is for vehicle loads and for slabs over poor ground; on a patio it adds cost without adding much.
What will the materials for this cost?
A planning range of $841 to $1,336 for everything in the shopping list, with $1,053 as the realistic middle. That is materials only: it excludes labour, delivery, tool hire and disposal of the old surface. Treat it as a budgeting figure, not a quote.