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Prices updated January 2026

How to Mix Concrete

By hand, from bags, or in a mixer — the water ratio, the steps, and how many bags your pour needs.

  1. 1

    Work out how many bags you need

    Before you open a bag, size the pour. Use the bags calculator to get the exact count for 40, 50, 60 or 80 lb bags so you don't run short mid-pour.

  2. 2

    Measure your water

    Each bag lists its water requirement — usually a few quarts per 80 lb bag. Start with about 80% of it and add the rest slowly; too much water weakens the concrete.

  3. 3

    Combine and mix

    Add the dry mix to the water (not the other way round) in a wheelbarrow, tub or mixer. Fold and turn until every bit is wet and uniform, with no dry pockets.

  4. 4

    Check the consistency

    Aim for a stiff, workable mix that holds a ridge when you drag a trowel through it — like thick oatmeal. If it slumps flat, it's too wet; add a little dry mix.

  5. 5

    Place it promptly

    Mixed concrete starts setting immediately — place, screed and finish within about 30–60 minutes, and only mix what you can place in that window.

How many bags do I need? →
Prices updated January 2026 National US averages · reviewed quarterly

Volumes use standard bag yields and a 10% waste allowance; costs are national US averages that vary by region, mix and finish. See our methodology for exactly how each figure is worked out, or check the reference sources:

Concrete calculators

Concrete Calculator Any shape: yards, bags & cost Concrete Slab Calculator Slabs & floors Concrete Footing Calculator Strip & continuous footings Concrete Wall Calculator Foundation & retaining walls Concrete Column & Tube Calculator Columns, piers, sonotubes Concrete Stairs Calculator Solid poured steps Concrete Yardage Calculator By the cubic yard Bags of Concrete Calculator 40 / 50 / 60 / 80 lb bags Concrete Slab Cost Price per square foot

Frequently asked questions

What is the water-to-concrete ratio?
Follow the bag: most 80 lb concrete mixes need roughly 3 quarts (about 0.75 gallon) of water per bag. Add most of it first, then the rest gradually — excess water is the number-one cause of weak, cracked concrete.
How do you mix concrete by hand?
Empty the bags into a wheelbarrow or mixing tub, make a well in the middle, add water, and fold the dry mix in with a hoe or shovel until uniform. Mix only what you can place in 30–60 minutes.
How many bags of concrete do I need?
That depends on the volume. An 80 lb bag makes about 0.60 ft³. Use the bags calculator to get the exact count for your slab or footing.
Can you pour concrete mix dry?
For fence posts you can pour fast-setting mix in dry and wet it in the hole. For slabs and structural work, always mix to the correct consistency first.