Concrete vs Cement: What's the Difference? (They're Not the Same!)

The #1 Misconception in Construction

Walk into any hardware store and you'll hear people use "concrete" and "cement" interchangeably. But they're not the same thing—and understanding the difference matters for your project.

The short answer: Cement is an ingredient IN concrete. Concrete is the finished building material.

Think of it like this: flour is to cake as cement is to concrete. You wouldn't call a cake "flour," and you shouldn't call concrete "cement."

What Is Cement?

Cement is a fine gray powder made by heating limestone and clay to extremely high temperatures (about 2,700°F), then grinding the result into powder. This powder, called Portland cement, is the "glue" that holds concrete together.

Cement alone is NOT a building material. It's too expensive, too weak, and cracks badly when used by itself. Its only purpose is to bind other materials together.

Types of Cement

• Portland cement (Type I): General purpose, most common
• Type II: Moderate sulfate resistance
• Type III: High early strength (faster curing)
• Type IV: Low heat of hydration (for massive pours)
• Type V: High sulfate resistance

What Is Concrete?

Concrete is a mixture of:

• Cement (10-15%): The binding agent
• Water (15-20%): Activates the cement
• Aggregate (60-75%): Sand, gravel, and crushed stone
• Air (5-8%): Tiny air bubbles improve durability

When water mixes with cement, a chemical reaction called hydration begins. The cement forms crystals that bind the aggregate into a rock-hard mass. This process continues for years, though most strength develops in the first 28 days.

Side-by-Side Comparison

Property	Cement	Concrete
What it is	Binding powder	Complete building material
Composition	Calcium, silicon, iron, aluminum	Cement + water + aggregate
Used alone?	Never	Yes
Strength	Weak alone	Very strong (3000-6000+ PSI)
Cost	$12-15 per 94 lb bag	$5-7 per 60-80 lb bag (pre-mixed)
Sold as	Portland cement	Quikrete, Sakrete, ready-mix

What About Mortar?

You'll also see mortar at the hardware store. Mortar is similar to concrete but made with finer sand and no large aggregate. It's designed to bond bricks, blocks, and stone—not for structural use.

Never substitute mortar for concrete in load-bearing applications. It's not strong enough.

What Should You Buy?

For Most DIY Projects: Bagged Concrete Mix

Pre-mixed concrete (like Quikrete or Sakrete) contains cement, sand, and gravel in the right proportions. Just add water. Use for:

• Fence posts
• Deck footings
• Small slabs
• Steps and walkways
• Repairs

For Large Projects: Ready-Mix Concrete

For pours over 1 cubic yard, order ready-mix delivered by truck. It's mixed precisely at the plant and arrives ready to pour. Use for:

• Driveways
• Garage floors
• Foundations
• Large patios

When to Buy Pure Cement

Very rarely for DIY. You might need Portland cement if you're:

• Making your own concrete mix (not recommended for beginners)
• Mixing mortar from scratch
• Creating specialized mixes

Calculate Your Concrete Needs

Now that you know you need concrete (not cement!), use our concrete calculator to determine exactly how much. Enter your project dimensions and get precise bag counts or cubic yard quantities.

Quick Terminology Guide

• Cement: Gray powder, binding ingredient
• Concrete: Cement + water + aggregate = building material
• Mortar: Cement + water + fine sand = for bonding masonry
• Grout: Similar to mortar, used to fill gaps
• Ready-mix: Concrete delivered by truck
• Bagged mix: Pre-mixed dry concrete in bags

The Bottom Line

Next time someone says "cement driveway" or "cement patio," you'll know they really mean concrete. Cement is just one ingredient—the glue that makes concrete strong. For any structural or load-bearing project, you need concrete, not cement.