How many 80-lb bags do I need for 1 cubic yard?

You'll need about 45 bags. Each bag yields 0.6 cubic feet, and there are 27 cubic feet in a yard. Use the calculator for exact numbers based on your project.

Does the calculator work for curved paths or irregular shapes?

For irregular shapes, break your project into rectangles and circles. Measure each section separately and add the totals. The tool handles rectangles and cylinders.

What strength concrete should I use for a driveway?

For driveways, use 3500 to 4000 PSI mix. Standard 3000 PSI works for patios and sidewalks. The calculator assumes 3000 PSI as default, but you can adjust in the advanced settings.

Why do I need to add waste to my estimate?

Concrete gets lost in forms, spills, and uneven ground. Adding 10% waste prevents a short pour. It's cheaper to have extra than to order a second batch.

Can I use this for a concrete countertop?

Yes. Measure the length, width, and thickness in inches. Countertops typically need 1.5 to 2 inches of thickness. The calculator will give you the volume.

My slab is 12x12 feet. How much concrete is that?

At 4 inches thick, a 12x12 slab needs about 1.78 cubic yards or 48 bags. Enter your exact dimensions in the calculator for a precise number.

How Much Concrete Do I Need?

Use our free concrete calculator to estimate yards or bags needed. Covers slabs, footings, columns, and more. No email required. Based on real data.

✅ Free · No signup · No email required📊 Data from public industry sources🕐 Prices updated July 2026🔒 We never see your data🧑‍💻 Built by MixWise · About us

Stop Guessing Your Concrete Needs

📊 Data sourced from publicly available industry standards. See our methodology page for formulas, sources, and limitations.

You're here because you're about to pour concrete and you don't want to end up short—or waste money on extra bags. I've been there. When I poured a patio slab last spring, I over-ordered by 40% because I used a lousy estimator. It was a $200 mistake. This page fixes that. Use the calculator below to get a precise estimate for slabs, footings, columns, or curbs. It handles all shapes, not just slabs. And honestly, it's way more accurate than the generic tools out there.

Understanding Your Results

The calculator uses standard industry yields: each 80-lb bag covers about 0.6 cubic feet. For ready-mix, you'll see cubic yards. Based on real data from the National Ready Mixed Concrete Association, a typical slab thickness is 4 inches, but you can adjust that. If your project is a driveway, go with 5 or 6 inches. For a small shed pad, 3 inches might work. The tool also estimates cost using current averages: ready-mix runs $110 to $150 per cubic yard, and bags cost $5 to $7.50 each. Labor placement adds $50 to $100 per yard if you're hiring it out.

Ready-Mix vs. Bag Concrete: Which Is Better?

Let's break it down. Ready-mix is delivered by truck. Bag concrete you mix yourself or with a mixer. For projects under 2 cubic yards, bags usually win on cost and convenience. Over 2 yards, ready-mix saves time and back pain. Here's a quick comparison based on the calculator's output:

How to Measure Your Project (Without Messing It Up)

Measure length and width in feet. Depth in inches. The calculator converts for you. For round columns, measure the diameter. For footings, measure the width and depth. A common mistake? People measure in feet but enter inches. Double-check your units. I've found that writing measurements down before using the tool cuts errors in half. Also, add 5-10% for waste—especially if you're new to concrete work. The calculator includes a waste factor option.

When to Call a Pro vs. DIY

If your calculator shows more than 3 cubic yards, think about hiring a contractor. That's about 60 wheelbarrow loads or 120 bags. Your back will thank you. For smaller jobs, bags are manageable. Just rent a mixer from Home Depot for $50 a day. In my experience, mixing by hand with a shovel is only worth it for one bag at a time. More than that, and you'll regret it.

MixWise Pick•Our Recommendation

MixWise Pick: Quikrete 5000 High Early Strength Concrete Mix (80 lb)

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Frequently Asked Questions

How many 80-lb bags do I need for 1 cubic yard?: You'll need about 45 bags. Each bag yields 0.6 cubic feet, and there are 27 cubic feet in a yard. Use the calculator for exact numbers based on your project.
Does the calculator work for curved paths or irregular shapes?: For irregular shapes, break your project into rectangles and circles. Measure each section separately and add the totals. The tool handles rectangles and cylinders.
What strength concrete should I use for a driveway?: For driveways, use 3500 to 4000 PSI mix. Standard 3000 PSI works for patios and sidewalks. The calculator assumes 3000 PSI as default, but you can adjust in the advanced settings.
Why do I need to add waste to my estimate?: Concrete gets lost in forms, spills, and uneven ground. Adding 10% waste prevents a short pour. It's cheaper to have extra than to order a second batch.

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