How thick should a concrete patio be?

Four inches is the common starting point for a residential patio. Heavy masonry features, hot tubs, vehicle access, or weak subgrade can require a thicker or engineered slab.

How many bags of concrete do I need for a 10 by 10 patio?

A 10 × 10 ft patio at 4 inches thick needs about 36.7 ft³ with 10% waste—approximately 82 60-pound bags or 62 80-pound bags.

Should a patio use ready-mix or bags?

Small repairs and pads can suit bags, but a typical patio often needs more than one cubic yard. Ready-mix is usually easier for placing the slab continuously before it begins to set.

Patio Concrete Calculator

Estimate concrete for a patio using its length, width, and thickness. See cubic yards, bags, weight, waste allowance, and an editable ready-mix material estimate.

Patio Dimensions

Results update as you change the formed dimensions.

Length

Width

Slab thickness

Waste allowance

Ready-mix price

$/yd³

Order quantity

1.96yd³ with waste

Slab area

144ft²

Net volume

48ft³

Concrete weight

7,920lb · 4 tons

60 lb bags

118bags

80 lb bags

89bags

Estimated ready-mix material cost

$373

Includes $60 short-load fee when the order is under 3 yd³. Labor, base, forms, reinforcement, finishing, tax, and other delivery charges are excluded.

Patio Concrete Thickness and Volume

A 4-inch slab is typical for residential patios carrying people, furniture, and grills. Thicker sections may be needed for hot tubs, masonry kitchens, poor soils, or other concentrated loads.

Patio quantity depends on the formed footprint—not the nominal landscaped area. Include steps, thickened edges, and separate pads as additional volumes.

How to Calculate Concrete for a Patio

Multiply the formed length by width and slab thickness after converting thickness from inches to feet. Divide cubic feet by 27 for cubic yards, then add the selected waste allowance.

Rectangular slab order

yd³ = length (ft) × width (ft) × [thickness (in) ÷ 12] ÷ 27 × (1 + waste%)

Measure the inside of the forms. Calculate thickened edges, footings, ramps, and separate pads independently.

Patio Planning Checklist

Measure the inside dimensions of the forms and divide irregular patios into simple rectangles.
Slope the patio away from the house and keep finished elevations below door thresholds.
Plan control joints and isolation joints around columns, walls, and existing concrete.
Add separate volume for steps, footings, or thickened edges.