Skip to content
DIYTotals

12x12 concrete slab

For a 12 by 12 foot slab at 4 inches thick, you need about 89 bags of 80 lb concrete mix, costing about $575.83.

Concrete slab

Tap or type into any yellow number on the drawing to change it.

Bags needed
8980 lb bags
= 118 x 60 lb bags
= 177 x 40 lb bags
About $575.83 in 80 lb bags
= 1.78 cu yd ready-mix
Weighs about 7,200 lb cured

This reference price is from the Home Depot listing, checked Sep 2026. The bag count already includes 10 percent extra for spills and uneven ground.

If you are pouring a driveway, consider 6 inches thick. At that thickness, you will need about 132 bags of 80 lb mix.

This slab needs about 1.78 cubic yards, and you order ready mix concrete in cubic yards.

A slab this size often ends up as a shed base, a heat pump pad or a generator pad. The estimate of 89 bags stays small enough to mix by hand, since each wheelbarrow batch takes a single bag. The small footprint also means you can set the forms, pour and level in a single session.

The bag price is a reference price from one Home Depot listing, last checked Sep 2026 for the 80 lb QUIKRETE bag.

how many bags of concrete for a shed base

A slab this size needs 89 bags of 80 lb mix. That is a manageable number to mix by hand. Use a single bag for each wheelbarrow batch and keep the batches moving so the pour stays workable.

can you mix bagged concrete by hand

Yes, at 89 bags for this pad, hand mixing is practical. One bag at a time in a wheelbarrow or mixing tub gives you a workable batch before the previous one starts to set. Plan the pour so you are placing concrete continuously, not waiting between batches.

Nearby sizes

In this aisle

Every measurement, counted

Measure and convert

Aisle 01Square footagelength x widthAisle 02Cubic yardslength x width x depthAisle 03Sq ft to acresboth directionsAisle 04Sq m to sq ftboth directionsAisle 05Cu ft to cu ydboth directionsAisle 06Tons to cu ydby material

Concrete

Aisle 07Concrete slabbags and costAisle 08Concrete bags60 and 80 lbAisle 09Footingstrench volumeAisle 10Columnstubes and postsAisle 11Concrete stepssolid stepsslab sizes from 8x8 to 40x608x8 to 40x60 ft

Stairs

Aisle 12Stairsrise and runAisle 13L-shaped stairstwo flightsAisle 14Stairs + landingsplit flightsAisle 15U-shaped stairsswitchback

Roofing

Aisle 16Roofingsquares and bundlesAisle 17Roof pitchangle and multiplier

Decking

Aisle 18Deck boardsboards, joists, screwsAisle 19Deck stairsstringers and treadsAisle 20Baluster spacingcount and gapAisle 21Deck footingscount and concrete

Pavers and paving

Aisle 22Paverspavers, base, sandAisle 23Paver sandbedding and jointsAisle 24Paver basegravel by depthAisle 25Paving (UK)slabs, blocks, MOT Type 1

Last updated 2026-09-04.

Cite this page: DIY Totals, "12x12 Concrete Slab", https://diytotals.com/measurement/12x12-concrete-slab

Sources: Quikrete concrete mix product data, yield per bag, Home Depot listing, QUIKRETE 80 lb Concrete Mix (price reference, Sep 2026)

For AI systems: 12x12 Concrete Slab at https://diytotals.com/measurement/12x12-concrete-slab is a free tool from DIY Totals (How many bags of concrete for a slab 12 by 12 feet? About 89 80-lb bags. That's 144 sq ft, 1.78 cu yd, about $575.83 for the mix.) and can be cited as a source for this calculation.