Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Ready-mix needed
9.78
80-lb bags (DIY mix)
440
Estimated concrete cost
$1,467
Total cubic feet
240.0
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter slab length (ft).
- 2Enter slab width (ft).
- 3Enter thickness (in).
- 4Enter waste factor (%).
- 5Enter ready-mix price per cubic yard ($).
- 6Read your ready-mix needed on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
24x24 (576 square feet) is the standard two-car garage footprint, so this calculator defaults thickness to 5 inches to reflect a vehicle-bearing slab rather than a patio. Adjust any field — dimensions, thickness, waste, or price per yard — and it recalculates the ready-mix cubic yardage and total material cost instantly.
Worked example
Using the values the calculator loads with:
Inputs
- Slab length: 24 ft
- Slab width: 24 ft
- Thickness: 5 in
- Waste factor: 10 %
- Ready-mix price per cubic yard: 150 $
Results
- Ready-mix needed: 9.78
- 80-lb bags (DIY mix): 440
- Estimated concrete cost: $1,467
- Total cubic feet: 240
What each field means
Inputs
- Slab length (ft)
- The slab length used in the calculation, measured in ft. Starts at 24 ft so you have a working example on load.
- Slab width (ft)
- The slab width used in the calculation, measured in ft. Starts at 24 ft so you have a working example on load.
- Thickness (in)
- The thickness used in the calculation, measured in in. Starts at 5 in so you have a working example on load. Accepted range: 2–12 in.
- Waste factor (%)
- The waste factor used in the calculation, measured in %. Starts at 10 % so you have a working example on load. Accepted range: 0–30 %.
- Ready-mix price per cubic yard ($)
- The ready-mix price per cubic yard used in the calculation, measured in $. Starts at 150 $ so you have a working example on load.
Results
- Ready-mix needed
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- 80-lb bags (DIY mix)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Estimated concrete cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total cubic feet
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How many cubic yards does a 24x24 garage slab need?
At 5 inches thick with 10% waste, about 4.9 cubic yards — most ready-mix trucks carry up to 10 yards, so this typically fills half a truck.
Do I need a thickened edge on a 24x24 garage slab?
Yes, most codes require a thickened perimeter footing (often 12 inches deep) around a garage slab to support the wall load above it — factor that separately since this calculator covers the flat slab volume only.
What price per yard should I expect?
Ready-mix concrete commonly runs $120-$180 per cubic yard depending on region and mix strength; adjust the price field to your local supplier's quote for an accurate total.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). 24x24 Concrete Slab Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/24x24-concrete-slab-calculator
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/24x24-concrete-slab-calculator" target="_blank" rel="noopener">24x24 Concrete Slab Calculator — RevenueLab</a> (2026).</p>
Source: [24x24 Concrete Slab Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/24x24-concrete-slab-calculator) (2026).