Use these free concrete calculators to quickly estimate the amount of concrete needed for slabs, footings, or columns. It is always best to round your estimate up, so you never come up short during a pour.

Concrete Slab Calculator

Enter the depth, width and length of your concrete slab to calculate the number of cubic yards or meters, and how many bags you'll need.

Concrete slab diagram
in
ft
ft

Volume of Concrete

0 Yards

How many pre-mix bags

40# Bags 0 bags
60# Bags 0 bags
80# Bags 0 bags

Concrete Footing Calculator

Enter the depth, width and length of your footing to estimate how much concrete you'll need.

Concrete footing diagram
in
in
ft

Volume of Concrete

0 Yards

How many pre-mix bags

40# Bags 0 bags
60# Bags 0 bags
80# Bags 0 bags

Concrete Column Calculator

Enter the diameter and height of your column to calculate how much concrete you'll need.

Concrete column diagram
in
in

Volume of Concrete

0 Yards

How many pre-mix bags

40# Bags 0 bags
60# Bags 0 bags
80# Bags 0 bags

CONCRETE CALCULATOR FAQs

How do I calculate how much concrete I need?

To calculate the amount of concrete required, use a concrete calculator or the basic formula:
Length × Width × Thickness. Convert the results to cubic feet or cubic meters, then divide by 27 to get cubic yards.

For additional industry guidelines, visit the American Concrete Institute: ACI Standards.

Pro Tip: The “Magic Number 81” Formula

If you are pouring a 4-inch slab, you can quickly estimate the concrete needed by dividing the total square footage by 81.

Example: 200 sq ft ÷ 81 = 2.46 cubic yards

What is the standard thickness for concrete?

Standard concrete thickness varies:

  • 4 inches for patios, sidewalks, and most driveways
  • 5–6 inches for garage floors or heavy-use driveways
  • 6–8+ inches for commercial slabs

For help choosing the right slab thickness, visit: AMC Construction Services.

Industry material standards: ASTM Concrete Guidelines.

How much is one yard of concrete?

One cubic yard equals 27 cubic feet. For example, a 10 ft × 10 ft slab at 4 inches thick needs just over 1 cubic yard.

How much concrete do I need for a 10×10 slab?

Concrete required depends on thickness:

  • 4-inch slab: approx. 1.24 cubic yards (56 bags of 80 lb concrete)
  • 6-inch slab: approx. 1.85 cubic yards (84 bags)

Use a concrete calculator for exact results or request an estimate here: AMC Concrete Contact Page.

How many 80 lb bags do I need?

Each 80 lb bag yields approximately 0.022 cubic yards. For a 100 sq ft slab at 4 inches, you’ll need about 56 bags.

Bag yield source: Quikrete

How many cubic feet does a 50 lb bag produce?

A 50 lb bag yields about 0.375 cubic feet.

Should I order by the yard or use bagged concrete?

Order ready-mix by the yard for:

  • Driveways
  • Large patios
  • Garage slabs

Use bagged concrete for:

  • Small walkways
  • Small pads
  • Footings
  • DIY repairs

Learn more from the Ready-Mix Concrete Association:NRMCA

Adding color to your concrete?

If you’re using integral color, calculate pigment based on cubic yards. Use the Solomon Colors calculator for accuracy: Solomon Colors.

How much does concrete cost per square foot?

Expect to pay $5.50 to $9.00 per sq ft for a standard concrete slab. Prices vary by slab thickness, reinforcement, and finish.

Local pricing available here: AMC Concrete.

How much does concrete weigh?

One cubic yard of concrete weighs approximately 4,000 lbs. So three yards weigh roughly 12,000 lbs.

Concrete Estimating Tips (Pro Level)

  • Always order more concrete than calculated.
  • Add 1/4 inch to estimated slab thickness for safety.
  • Convert irregular shapes into rectangles to simplify calculations.
  • Calculate porches and steps separately using slab + footing calculators.

For professional concrete services in Tennessee, contact AMC Concrete