Best Concrete Mixers for DIY Slabs and Posts (2026)

What to look for in a concrete mixer

For bagged concrete, the specs that matter are the ones that say how many bags go in at once and how each batch gets from the drum to the form or the post hole:

• Batch size, not just drum size. A drum mixes less than it holds. IMER gives its 5 cu ft drums a batch output of 2.5 cu ft, and Stark gives its 5 cu ft drum a mixing capacity of 2.5 cu ft or 270 lb. The next section turns those figures into bags.
• A household outlet. All four drum mixers here plug into ordinary household power: IMER lists 120 V and Stark 110 V, from a 1/2 hp motor up to the Multi-Mix 350's 2 HP.
• How the batch leaves the drum. The Wheelman II is built like a wheelbarrow: mix, roll it to the form and dump it from 8 in (21 in on the optional stand). The Minuteman pours from 21 in and the Stark from 23 in. On both the Wheelman II and the Minuteman, one person can lift the drum out to load the mixer into a small vehicle.
• Weight you can move. IMER publishes 110 lb for the Minuteman and 385 lb for the Multi-Mix 350. Stark publishes none, and the Wheelman II page lists two weights without saying which one is the electric model, so we leave it out.
• For cordless mixers, buckets per charge. DEWALT says how many buckets of concrete one charge mixes; Milwaukee gives a bucket count without naming the material. Neither lists a mixing paddle in the box, and the Milwaukee comes without a battery or charger.

The spec comparison above shows batch size, power and type for every pick. Drum size, pour height, wheels and weight, where the maker publishes them, are on each pick's card.

Bags per batch: drum size vs batch output

QUIKRETE's data sheet for its Concrete Mix sets the first limit: allow at least 1 cu ft of mixer capacity for each 80 lb bag mixed at one time. An 80 lb bag makes 0.60 cu ft of concrete (see concrete bag yields), so a published batch output sets the second. A published load limit sets the third, and it has to include the water: QUIKRETE puts the final mix at 6 to 9 pints of water per bag, and at the heaviest weight in the USGS water table, 62.424 lb per cu ft, 9 pints weigh 9.39 lb. The fewest bags any of the three allows is the batch.

Drum rule     = drum cu ft ÷ 1 cu ft per bag (QUIKRETE)
Batch output  = batch cu ft ÷ 0.60 cu ft per 80 lb bag
Load limit    = load lb ÷ (80 lb + 9 pt of water) = load ÷ 89.4 lb
9 pt of water  = 9 ÷ 8 gal × 231 in³ ÷ 1,728 × 62.424 lb/cu ft = 9.39 lb
IMER Wheelman II   = fewest of 5 ÷ 1 = 5, 2.5 ÷ 0.60 = 4 → 4 bags
IMER Minuteman     = fewest of 5 ÷ 1 = 5, 2.5 ÷ 0.60 = 4 → 4 bags
Stark USA 67001    = fewest of 5 ÷ 1 = 5, 2.5 ÷ 0.60 = 4, 270 ÷ 89.4 = 3 → 3 bags
IMER Multi-Mix 350 = fewest of 12 ÷ 1 = 12, 9.5 ÷ 0.60 = 15 → 12 bags

The concrete calculator's default slab, 10 × 10 ft and 4 in thick with a 10% allowance, takes 62 bags of 80 lb mix. Divide by the bags per batch and round up:

62 bags ÷ bags per batch, rounded up. Bags per batch round down, because a mixer cannot take part of a bag over its limit. Stark's batch reads its 270 lb as the whole wet load: 3 bags with 9 pints of water each weigh 268.2 lb.

Fence posts work the same way, one hole at a time. The fence post guide's example, a 4×4 in a 12 in hole 36 in deep, set the way QUIKRETE describes for its Concrete Mix, has 6 in of dry mix poured from the bag under the post and mixed concrete around it. The mixed part is 1.75 cu ft, or 3 bags, so every drum mixer here fills one hole per batch; buy about 0.65 bag more per hole for the dry mix. Fast-setting mix is poured dry into the hole and wetted there, so it needs no mixer at all.

A cordless mixer works bucket by bucket. DEWALT says the DCD130 mixes up to 9 buckets of concrete of 4.5 gal each on one charge of the kit's battery. 4.5 gal is 0.60 cu ft, the concrete from one 80 lb bag, so a charge covers 9 bags: 3 post holes, or 4 charges for 10 posts, but 7 charges for the 62-bag slab. Milwaukee's 15 buckets per charge name no material, so we leave the 2810-20 out of these counts.

Drum mixer, paddle mixer or ready-mix?

For a few posts or a repair, a cordless mixer and a bucket or tub are enough, and QUIKRETE also allows its Concrete Mix to be mixed by hand with a shovel or hoe in a mixing container. For a slab, a drum mixer keeps the pour moving: at 4 bags a batch the 62-bag slab is 16 batches, and at 12 bags a batch, 6. The slab guide covers forms, mixing water, placing and curing.

Past a few dozen bags, compare the bag count with a ready-mix delivery: the concrete calculator gives both, and the bagged vs. bulk guide walks through the trade-offs. To move each batch to the form, see the best wheelbarrows for concrete and gravel; every tool on this page is also listed with the rest in our top tool picks.