How many 80 lb bags of concrete make one cubic yard?

One cubic yard contains 27 cubic feet. A standard 80 lb pre-mix concrete bag yields 0.60 cubic feet when mixed. It takes 45 bags of 80 lb concrete to equal one full cubic yard.

How thick should a concrete patio or walkway be?

Standard residential walkways, patios, and shed floors should be 4 inches thick. Driveways supporting vehicles should be poured at 5 to 6 inches thick with rebar or wire mesh reinforcement.

When should I order a concrete truck instead of mixing bags?

If your project requires more than 1 cubic yard (45 bags of 80 lb concrete), mixing by hand or small mixer becomes exhausting and risks 'cold joints'. For projects over 1.5 to 2 cubic yards, ordering a transit mix truck is faster and more uniform.

What is the formula for cubic yards of concrete?

For a rectangular slab: (Length in feet × Width in feet × Thickness in feet) / 27. (Note: Divide thickness in inches by 12 first to convert to feet).

Why should I add 10% extra concrete to my order?

Earth excavations are never perfectly flat. Uneven ground, settling forms, and slight grade dips invariably consume 5% to 10% more concrete than nominal math predicts. Running short by half a bag ruins the finish.

DIY & Trades100% Client-Side Local Execution•Updated 2026

Concrete Slab, Footing & Pre-Mix Bag Volume Calculator

Name: Concrete Slab, Footing & Pre-Mix Bag Calculator
Author: AnshuTechy

Calculate required concrete volume in cubic yards and cubic meters, and determine exact bag counts for 60 lb and 80 lb ready-mix concrete bags.Documentation & FAQs ↓

Concrete Slab, Footing & Pre-Mix Bag Calculator — Interactive Console

Runs locally in your browser • Instant output

Slab Length (Feet)

Slab Width (Feet)

Thickness (Inches)

Waste Allowance (10%)Accounts for uneven ground & forms

Cubic Yards Needed1.63 yd³For ready-mix truck delivery

80 lb Bags Needed74 Bags0.60 cu ft per bag

60 lb Bags Needed98 Bags0.45 cu ft per bag

Total Cubic Feet44.0 ft³Includes 10% waste

Step-by-Step Instructions

4 Steps to Completion

1Phase 1

Select structure type: Rectangular Slab or Round Footing / Pier.

2Phase 2

Enter dimensions: Length, Width, and Thickness (inches, typically 4" for patios).

3Phase 3

Choose your preferred bag size (60 lb or 80 lb ready-mix).

4Phase 4

Review total cubic yards, cubic meters, and exact bags to purchase.

Practical Use Cases & Real-World Scenarios

Pouring a Concrete Patio Slab

Determine whether mixing bags yourself is economical or if calling a ready-mix truck is required.

Setting Fence Posts & Deck Footings

Calculate exactly how many bags of Quikrete are needed per 10-inch or 12-inch post hole.

Contractor Material Ordering

Order concrete ready-mix trucks with the precise cubic yardage to avoid 'short-load' penalty fees.

Concrete Slab, Footing & Pre-Mix Bag Volume Calculator

Step-by-Step Instructions

Practical Use Cases & Real-World Scenarios

Rectangular & Circular Shapes

Standard Pre-Mix Bag Presets

Cubic Yards & Metric Conversion

Spillage & Sub-Base Buffer

Frequently Asked Questions

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