What a 10x12 slab is for
A 10x12 slab is the base for a common shed size, and it makes a small patio with room for a round table for four and its chairs. With the long side against the house, the extra 2 feet go where the door is.
Concrete for a 10x12 slab at 4, 5 and 6 inches
Every inch of thickness on a 10x12 slab is 10 cubic feet, or 0.37 cubic yards. The ready mix order and the bags in this table include 10 percent extra. Change the thickness or the extra in the calculator above.
| Thickness | Cubic feet | Cubic yards | Ready mix to order | 80 lb bags | 60 lb bags |
|---|---|---|---|---|---|
| 4 in | 40 | 1.48 | 1.63 cu yd | 74 | 98 |
| 5 in | 50 | 1.85 | 2.04 cu yd | 92 | 123 |
| 6 in | 60 | 2.22 | 2.44 cu yd | 110 | 147 |
The 4 inch row by hand: 12 × 10 × 0.333 = 40 cubic feet, and 40 ÷ 27 = 1.48 cubic yards. With 10 percent extra that is 44 cubic feet. An 80 lb bag makes 0.60 cubic feet and a 60 lb bag makes 0.45, so it takes 74 of one or 98 of the other.
Quikrete says a sidewalk should be at least 4 inches thick and small slabs normally run 4 to 6 inches, depending on the load. The concrete slab calculator page covers what the building code asks for.
Bags or a truck for a 10x12 slab
From bags, it is 74 bags of 80 lb mix at 4 inches, 5,920 lb to lift and mix, about $421 at McCoy's price of $5.99 a bag, or $5.69 for 42 or more.
From a truck, it is 1.63 cubic yards, about $179 to $244 at HomeAdvisor's $110 to $150 per cubic yard delivered. The National Ready Mixed Concrete Association says a truck mixer carries 8 to 12 cubic yards, so this is less than one truck load. HomeAdvisor says an order under a full truckload can carry a short-load fee of $40 to $60 per cubic yard, and suppliers often have a minimum order.
By these prices a 10x12 slab costs about $177 to $242 less from a truck than from bags, and it saves lifting 5,920 lb of mix. A short-load fee or a minimum order comes out of that gap, so get a delivered price for 1.63 cubic yards and compare it with $421. It is a bag job only if that quote comes in higher or a truck cannot reach the slab. The association notes that a loaded truck weighs about 80,000 lb and may not be able to cross loose dirt or a residential curb.
| Thickness | 80 lb bags | Bags weigh | Bags cost | Ready mix | Ready mix cost |
|---|---|---|---|---|---|
| 4 in | 74 | 5,920 lb | $421 | 1.63 cu yd, less than one truck load | $179 to $244 |
| 5 in | 92 | 7,360 lb | $523 | 2.04 cu yd, less than one truck load | $224 to $306 |
| 6 in | 110 | 8,800 lb | $626 | 2.44 cu yd, less than one truck load | $268 to $366 |
Prices are from the sources below, checked in October 2026; multiply the table by your own to compare. Gravel, steel, forms, finishing and labor are extra.
Pouring a 10x12 slab
The slab still screeds with one 12 foot board run across the 10 foot width. At about 1.6 cubic yards, it is a short load for a truck, so ask the plant for its minimum order and its short-load fee before you choose. Mixing by hand means 74 bags, which is a long day for two people with a mixer.
Gravel base and slope
A 4 inch gravel base under a 10x12 slab is 40 cubic feet, or 1.48 cubic yards. Quikrete says to spread and compact 3 to 4 inches, and a 3 inch base is 30 cubic feet, or 1.11 cubic yards. Those are volumes of the finished layer. Gravel settles when it is compacted, so order a little more.
Outside, Quikrete says to slope the slab away from buildings and gives 1/4 inch per foot as the usual fall. Running across the 10 foot side, that is 2 1/2 inches from one edge to the other. Running along the 12 foot side, it is 3 inches. Set the forms to the slope, and the screed follows them.
Rebar or wire mesh
With bars 24 inches on center both ways, held 3 inches back from each edge, a 10x12 slab takes 6 bars 11 feet 6 inches long and 7 bars 9 feet 6 inches long. That is 136 feet of bar. With 10 percent extra, buy 8 bars 20 feet long. Every bar is shorter than the 20 foot length sold, so none has to be joined.
With wire mesh instead, 2 sheets 8 feet by 12.5 feet, lapped 8 inches, cover it. The spacing and the sheet size are where the calculator starts. Your plans or your building department set the steel for your slab.
Control joints
Quikrete says control joints in a 4 inch slab go every 6 to 8 feet and about a quarter of the slab deep, which is 1 inch. Keeping them no more than 8 feet apart cuts a 10x12 slab into 2 panels along the 12 foot side and 2 along the 10 foot side. That makes 4 panels, each 6 feet by 5 feet, with 22 feet of joint to cut.
Before you pour a 10x12 slab
At exactly 120 square feet, a 10x12 shed sits right on a line some towns draw. The model code for houses (IRC R105.2) lets sheds up to 200 square feet skip the building permit, but some towns use a lower limit, such as 120 square feet. Check yours before you buy the kit.
Other slab sizes
8x1010x1010x1212x1210x2012x2016x2020x2020x2424x2424x3030x40
Common questions
How much concrete do I need for a 10x12 slab?
A 10 by 12 foot slab 4 inches thick holds 40 cubic feet of concrete, which is 1.48 cubic yards. With 10 percent extra, order 1.63 cubic yards of ready mix. At 5 inches thick it holds 1.85 cubic yards and at 6 inches 2.22.
How many 80 lb bags of concrete do I need for a 10x12 slab?
74 bags at 4 inches thick, with 10 percent extra. They weigh 5,920 lb in all and cost about $421 at the store price checked in October 2026. At 5 inches thick it is 92 bags and at 6 inches 110.
How thick should a 10x12 concrete slab be?
Quikrete calls for at least 4 inches for a sidewalk and 4 to 6 inches for small slabs, depending on the load. The International Residential Code minimum for a house floor slab is 3.5 inches. On a 10x12 slab each extra inch adds 0.37 cubic yards, so going from 4 to 6 inches takes the ready mix order from 1.63 to 2.44 cubic yards. Ask your building department what it wants for a driveway or a garage floor.
Should a 10x12 shed slab be bigger than the shed?
No. Pour it to the outside size of the shed walls. Concrete sticking out past the walls catches the rain running down the siding and sends it under the sill, where it rots the wood.
Does a 10x12 shed need a permit?
Under the model code, usually not: IRC R105.2 lets a one-story detached shed of up to 200 square feet go without a building permit. Some towns set a lower limit, often 120 square feet, which is exactly the size of a 10x12. Ask your building department.
Tools for this job
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- Form stakes. Hold the form boards in place while you pour.
- Concrete float. Smooths the surface after the concrete is leveled.
- Edger. Rounds the slab edges so they do not chip.
- Groover. Cuts control joints so cracks follow a straight line.
- Finishing trowel. Gives the slab its final smooth surface.
- Rubber boots. Keep wet concrete off your skin while you stand in the pour.
Sources
- Quikrete, Pouring and Finishing Concrete Slabs
- Quikrete, Concrete Sidewalks and Small Slabs project guide
- Quikrete Concrete Mix data sheet (yield per bag)
- National Ready Mixed Concrete Association, CIP 31: Ordering Ready Mixed Concrete
- International Residential Code 2021, Chapter 5: concrete floors on the ground (R506)
- International Residential Code 2021, Chapter 4: foundations (R403, concrete cover over steel)
- Wire Reinforcement Institute, Manual of Standard Practice: Structural Welded Wire Reinforcement
- City of Dubuque, Iowa, minimum requirements for a detached garage slab
- City of Fridley, Minnesota, Garage Slabs handout
- PJ's Rebar, stock rebar sizes and lengths
- International Residential Code 2021, Chapter 1: work exempt from permit (R105.2)
- McCoy's Building Supply: Quikrete Concrete Mix, 80 lb bag
- HomeAdvisor: concrete delivery cost, per cubic yard and short-load fees
Facts on this page were last checked against these sources in October 2026.