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
1.36
80-lb bags (DIY mix)
61
Estimated concrete cost
$204
Total cubic feet
33.3
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter slab length (ft).
- 2Enter slab width (ft).
- 3Enter thickness (in).
- 4Enter waste factor (%).
- 5Enter ready-mix price per cubic yard ($).
- 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
A 10x10 slab is the go-to footprint for a small patio, shed pad, or utility pad, and the math is the same every time: length times width times thickness gives you volume, which you convert to cubic yards for ready-mix or bags for a DIY pour. This calculator starts at 10 feet by 10 feet with a standard 4-inch thickness so you can get a number immediately, but every field is editable if your actual pad is a little different. It adds a waste factor for spillage and uneven subgrade, then gives you both the ready-mix cubic yardage to order and the bag count if you're mixing 80-lb bags by hand, plus the total material cost at your local price per yard.
Worked example
Using the values the calculator loads with:
Inputs
- Slab length: 10 ft
- Slab width: 10 ft
- Thickness: 4 in
- Waste factor: 10 %
- Ready-mix price per cubic yard: 150 $
Results
- Ready-mix needed: 1.36
- 80-lb bags (DIY mix): 61
- Estimated concrete cost: $204
- Total cubic feet: 33.3
What each field means
Inputs
- Slab length (ft)
- The slab length used in the calculation, measured in ft. Starts at 10 ft so you have a working example on load.
- Slab width (ft)
- The slab width used in the calculation, measured in ft. Starts at 10 ft so you have a working example on load.
- Thickness (in)
- The thickness used in the calculation, measured in in. Starts at 4 in so you have a working example on load. Accepted range: 2–12 in.
- Waste factor (%)
- The waste factor used in the calculation, measured in %. Starts at 10 % so you have a working example on load. Accepted range: 0–30 %.
- Ready-mix price per cubic yard ($)
- 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
Is 4 inches thick enough for a 10x10 slab?
Yes for patios, sheds, and walkways. Bump to 5-6 inches if a vehicle will ever park on it, since foot-traffic-only slabs and driveway-rated slabs have very different load requirements.
Should I order ready-mix or mix bags myself for 10x10?
At 4 inches thick a 10x10 slab is about 1.4 cubic yards, which is right at the edge — many contractors will still deliver ready-mix for a small minimum-load fee, and it cures more consistently than dozens of hand-mixed bags.
Why add a waste factor?
Subgrade is never perfectly flat, forms leak a little, and spillage happens during placement. A 10% waste factor covers typical conditions; rocky or sloped sites often warrant 15%.
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). 10x10 Concrete Slab Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/10x10-concrete-slab-calculator
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/10x10-concrete-slab-calculator" target="_blank" rel="noopener">10x10 Concrete Slab Calculator — RevenueLab</a> (2026).</p>
Source: [10x10 Concrete Slab Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/10x10-concrete-slab-calculator) (2026).