How much concrete for a 10x10 slab?

A 10 by 10 foot slab at 4 inches is about 1.23 cubic yards before waste. With 10 percent waste, order roughly 1.35 yards or about 56 eighty-pound bags.

How thick should a driveway slab be?

Many residential driveways use 5 to 6 inches of concrete over compacted aggregate. Local code and soil conditions may require more.

How many 80 lb bags equal a cubic yard?

About 46 bags of 80 lb mix per cubic yard using a 0.022 cubic yard yield per bag. Always round up.

Should I order ready-mix or bags for a patio slab?

Small patios under roughly 1.5 cubic yards are often bagged; larger pours usually favor ready-mix for speed and consistency.

What waste percentage should I use for slab concrete?

Five to ten percent is common on residential flatwork. Irregular shapes and over-excavation may need more.

How do I calculate slab volume in cubic yards?

Multiply length times width times thickness in feet for cubic feet, then divide by 27 for cubic yards.

Does a garage slab need rebar?

Many garage slabs use #4 or #5 rebar at 12 inches on center each way, but engineering and soil reports govern the final design.

How long should concrete cure before driving on it?

Many residential driveways need about 7 days before passenger vehicle traffic; follow your mix supplier guidance.

Concrete Calculator for Slabs & Slab Estimator

Q: How thick should a concrete slab be?

Patios and walks often use 4 inches; driveways and garages commonly use 5 to 6 inches. Soil, loads, and local code may require more.

Q: How many bags are in a cubic yard?

About 46 eighty-pound bags per cubic yard at 0.022 cubic yard yield each. Always round up for waste.

Q: How much does a concrete slab cost?

Ready-mix often runs 130 to 180 dollars per yard plus delivery. Use the cost field in the calculator and the concrete cost calculator for labor.

Concrete Coverage Chart

Square feet covered per cubic yard at common slab thickness values.

Coverage per cubic yard by slab thickness
Thickness	Sq Ft / Cu Yd	Typical Use
4 in	~81 sq ft	Patio, sidewalk, shed
5 in	~65 sq ft	Driveway (light)
6 in	~54 sq ft	Garage, driveway
8 in	~40 sq ft	Foundation mats, heavy flatwork

Practical Slab Examples

Tap to load into this concrete calculator for slabs.

10×10 Slab

10 ft × 10 ft × 4 in, 10% waste.

Volume: ~1.35 cu yd

20×20 Driveway Pad

20 ft × 20 ft × 5 in section.

Volume: ~6.2 cu yd

Garage Slab

24 ft × 24 ft × 6 in.

Volume: ~11.8 cu yd

Sidewalk Slab

4 ft × 50 ft × 4 in.

Volume: ~2.7 cu yd

How to Calculate Concrete for a Slab

V = L × W × D → Cu Yd = CF ÷ 27 Convert length, width, thickness to feet · add waste% · then bags & trucks

Measure slab length and width inside forms.
Convert thickness to feet (inches ÷ 12).
Multiply L × W × D for cubic feet.
Divide by 27 for cubic yards (ready-mix orders).
Add waste (typically 5–10%) before ordering.

This concrete slab volume calculator handles unit conversion, waste, bag yields, and truck loads automatically.

Cross-check with the concrete yard calculator and concrete volume calculator on the same footprint.

Slab Thickness Guide

Project	Typical Thickness	Notes
Patio	4 in	Light foot traffic, broom finish
Driveway	5–6 in	Passenger vehicles, control joints
Garage	5–6 in	Often reinforced, check soil report
Sidewalk	4 in	May use mesh on residential walks

Contractor Tips

Measure inside forms. Outside dimensions over-order concrete on every slab concrete estimate.
Match reinforcement to use. Use our rebar calculator and rebar spacing calculator after volume is set.
Plan curing before the pour. Hydration matters more than an extra half-yard—schedule water or compound.
Compare bags vs ready-mix. Below ~1.5 yards, bags can win; above that, truck delivery usually saves labor.
Budget with cost tools. Pair volume with the concrete cost calculator for line-item quotes.

Concrete for Slabs FAQ

How much concrete for a 10×10 slab?

A 10×10 ft slab at 4 inches is about 1.23 cubic yards before waste. With 10% waste, order ~1.35 yards or roughly 56 80 lb bags.

How thick should a concrete slab be?

Patios and walks often use 4 in; driveways and garages commonly use 5–6 in. Soil, loads, and local code may require more.

How many bags are in a cubic yard?

About 46 80 lb bags per cubic yard (0.022 cu yd yield each). Always round up for waste and spillage.

How much does a concrete slab cost?

Ready-mix often runs $130–$180 per yard plus delivery. Enter your local $/yd above and pair with our concrete cost calculator for labor.

How many cubic yards in a 24×24 garage slab at 6 inches?

Net volume is about 10.67 cubic yards before waste. With 10% waste, plan for roughly 11.7 yards.

Is 4 inches enough for a patio?

Many light-duty patios use 4 inches over compacted gravel. Heavy features like outdoor kitchens may need thicker sections per engineering.

How do 50 lb bags compare to 80 lb?

Fifty-pound bags yield about 0.014 cubic yards each versus 0.022 for 80 lb—you need more bags but lighter lifts.

What is a short load fee?

Ready-mix plants often charge extra below 4–6 yards. This slab tool helps you see when you are near truck minimums.

Should I add rebar to a shed slab?

Small sheds on good soil sometimes use mesh; larger loads or poor soil warrant #3 or #4 grid. Match your permit detail.

How is this different from the concrete slab calculator?

Same slab math — this page targets concrete calculator for slabs searches. Also see concrete slab calculator and the general concrete calculator.

Concrete Calculator for Slabs

Slab Diagram

10×10 Slab

20×20 Driveway Pad

Garage Slab

Sidewalk Slab

How to Calculate Concrete for a Slab

Slab Thickness Guide

Contractor Tips

Concrete for Slabs FAQ

Concrete Slab Calculator

Concrete Cost Calculator

Concrete Volume Calculator

Rebar Calculator

Cubic Yard Calculator

Concrete Calculator