Patio Concrete Calculator
By Vinod Kondeti · Updated
Patios often sit on ground that is hard to level perfectly. A low spot of half an inch across a 16 × 12 patio adds about 8 ft³. That is why the waste field matters more here than on smaller pours.
How do I measure for a patio pour?
- Measure the finished patio size inside the forms.
- Before you calculate, check the grade with a string line at several points.
- Round patios: area = π × r², then use the cubic yards page with that area × thickness.
Patio concrete questions
How many yards for a 16 × 12 patio at 4 in?
16 × 12 × 0.333 = 64 ft³ = 2.37 yd³ before waste, or 2.61 yd³ with 10% extra.
How many 80 lb bags is that?
About 107 bags without waste, or 118 with 10% extra. At that size most people order ready-mix.
Bag yields: 0.30 / 0.45 / 0.60 ft³ for 40 / 60 / 80 lb standard concrete mix (manufacturer data sheets). The concrete guide has the formulas and worked examples.
Sources
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