How do I calculate concrete yards for a slab?

Multiply length times width times thickness in feet for cubic feet, divide by 27 for cubic yards, then add your waste percentage before ordering.

How many cubic feet are in a yard of concrete?

One cubic yard equals 27 cubic feet. Divide your cubic feet total by 27 to get yards.

How many 80 lb bags equal one cubic yard?

About 46 bags of 80 lb mix per cubic yard at standard yield. Always round up.

How many truck loads is 15 cubic yards?

At 10 yards per truck, 15 cubic yards is about 1.5 truck loads. Round up for scheduling.

What waste percentage should I use?

Residential flatwork often uses 5 to 10 percent. Irregular forms or over-excavation may need more.

Is a concrete yard the same as a cubic yard?

Yes. Ready-mix plants quote in cubic yards; contractors often say concrete yards on the phone.

When should I use bags instead of ready-mix?

Small pours under roughly 1 to 1.5 yards are often bagged. Larger slabs usually favor truck delivery.

How does this differ from the main concrete calculator?

This page is yard-first for dispatch calls. The main concrete calculator adds more pour types and options.

Concrete Yard Calculator – Cubic Yards, Trucks & Bags

Concrete Coverage Chart

Square feet covered per cubic yard by thickness.

Coverage per cubic yard
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	Footing mat, heavy flatwork

Practical Examples

10×10 Patio

4 in thick, 10% waste.

20×20 Driveway

5 in thick section.

Garage Slab

24×24 ft, 6 in.

Sidewalk Section

4×50 ft, 4 in.

Cubic Yard Formulas

Cu Yd = (L × W × T) ÷ 27T in feet · multiply by (1 + waste%) before bags and cost

This concrete cubic yard calculator converts any unit to feet first. Use the concrete volume calculator for pure geometry, or concrete slab calculator for flatwork presets.

Concrete Ordering Guide

Round up on truck math. A 10.3-yard pour on a 10-yard truck still needs two tickets if you cannot short-load cheaply.
Confirm minimum load fees. Plants often charge extra below 4–6 yards—your concrete yard estimator output helps you compare bag vs truck break-even.
Add waste before comparing bids. Net geometry understates real orders; 5–10% is normal on residential slabs.
Match PSI at the plant. Yards are volume; mix design is separate—tell dispatch slab vs driveway use.
Pair with reinforcement. After yards are set, run concrete and rebar calculator or rebar calculator on the same footprint.

Concrete Yard FAQ

How many yards for a 12×20 driveway at 5 inches?

Net volume is about 3.7 yards before waste. With 10% waste, order roughly 4.1 yards.

Why divide by 27?

There are 27 cubic feet in one cubic yard (3×3×3 ft). Suppliers batch and bill in yards.

Does this calculate concrete cost?

Enter your local $/yd for a ready-mix line item. Labor, pump, and finishing are separate.

What is recommended ordering quantity?

The Order Quantity field shows cubic yards with your waste factor—the number to tell dispatch.

Concrete Calculator

Full volume, bags, and cost tool.

Open →

Concrete Slab Calculator

Slab-type presets and thickness guide.

Slab →

Concrete Volume Calculator

CF, CY, and m³ conversion.

Volume →

Rebar Calculator

Steel for the same pour.

Rebar →

Concrete Cost Calculator

Full slab budget with labor lines.

Cost →

Concrete And Rebar Calculator

Combined volume and steel.

Combined →