Concrete Calculator
Calculate concrete volume in cubic yards, bags needed, and total cost for slabs, footings, and columns. Free concrete calculator with real-time results.
Quick Start Presets
Choose a common scenario to get started instantly
Calculate Your Project
Enter your dimensions for instant, accurate results
Dimensions
Measure the area for your concrete slab
Additional Options
Waste allowance and cost estimation
Results
Your depth is appropriate for residential driveways. For this size project, ready-mix concrete delivery is recommended.
Your Personalized Summary
You need 2.47 cubic yards of concrete, or 2.72 cubic yards including 10% waste allowance. This equals approximately 111 bags of 80lb concrete mix and will cost around $380.
How Much Concrete Do I Need?
Calculating how much concrete you need is essential for budgeting and ensuring you have enough material for your project. The amount of concrete required depends on the volume of the space you're filling, measured in cubic yards (the standard unit for ordering ready-mix concrete).
To calculate concrete volume: multiply length × width × depth (all in feet), then divide by 27 to convert cubic feet to cubic yards. For example, a 20ft × 10ft driveway slab at 4 inches (0.33 feet) deep requires 2.47 cubic yards. According to the Portland Cement Association, proper volume calculation is critical for project success and cost control.
Always order 5-10% extra concrete to account for waste, spillage, uneven ground, and measurement variations. Our concrete calculator automatically includes this waste percentage in your results. For related construction projects, check our asphalt calculator for paving alternatives.
Pro Tip:
For slabs, always measure depth in inches and convert to feet (4 inches = 0.33 feet). This is the most common source of calculation errors.
How Many Yards of Concrete Do I Need?
Cubic yards are the standard measurement for ordering concrete. Here's a quick reference guide for common projects:
| Project Type | Dimensions | Cubic Yards | 80lb Bags |
|---|---|---|---|
| Small Patio | 10ft × 10ft × 4in | 1.23 yd³ | 55 bags |
| Driveway | 20ft × 10ft × 4in | 2.47 yd³ | 111 bags |
| Large Patio | 15ft × 15ft × 4in | 2.78 yd³ | 125 bags |
| Garage Floor | 20ft × 20ft × 4in | 4.94 yd³ | 222 bags |
| Sidewalk (50ft) | 50ft × 4ft × 4in | 2.47 yd³ | 111 bags |
| Foundation Footing | 40ft × 2ft × 1ft | 2.96 yd³ | 133 bags |
Important: Ready-mix concrete is sold by the cubic yard with minimum orders typically starting at 1 yard. Many suppliers charge extra fees for orders under 3-5 yards. For small projects under 1 cubic yard, bagged concrete mix is often more practical despite higher per-yard costs.
Use our concrete yard calculator above to get precise measurements for your specific project dimensions. The calculator automatically converts between cubic feet and cubic yards for your convenience.
How Much Does a Yard of Concrete Cost?
Concrete costs vary significantly by location, mix specifications, and delivery distance. Here's a comprehensive breakdown of concrete pricing:
Ready-Mix Concrete (Delivered)
- • Standard mix: $125-$150/yd³
- • High-strength mix: $150-$175/yd³
- • Fiber-reinforced: $140-$165/yd³
- • Colored concrete: $150-$200/yd³
- • Small load fee (under 5 yd³): +$50-$150
- • Delivery beyond 20 miles: +$10-$15/mile
Bagged Concrete Mix
- • 80lb bag: $4-$6 each
- • 60lb bag: $3-$5 each
- • Cost per cubic yard: $180-$270
- • 45 bags (80lb) = 1 cubic yard
- • 60 bags (60lb) = 1 cubic yard
- • Best for projects under 1 yd³
Cost Comparison Example: For a 2.5 cubic yard driveway project:
- Ready-mix delivery: 2.5 yd³ × $140 = $350 (more economical)
- Bagged concrete: 113 bags × $5 = $565 (plus significant labor)
According to industry data, ready-mix becomes cost-effective at around 1.5-2 cubic yards when factoring in labor time for mixing bags. For larger projects, ready-mix also ensures consistent quality and proper hydration, which is critical for structural strength.
Use our concrete cost calculator above to estimate your total project cost based on current local pricing. For financial planning of larger construction projects, check our HELOC calculator to explore financing options.
Concrete Slab Calculator: How to Calculate Volume
Calculating concrete for slabs is straightforward with the right formula. Here's the step-by-step process:
Step 1: Measure Dimensions
- Length: Measure the longest side in feet
- Width: Measure the shortest side in feet
- Depth: Measure thickness in inches (typical: 4-6 inches)
Step 2: Convert Depth to Feet
Divide inches by 12 to get feet. Common conversions:
- 4 inches = 0.33 feet
- 5 inches = 0.42 feet
- 6 inches = 0.50 feet
Step 3: Calculate Volume
Volume (yd³) = Volume (ft³) ÷ 27
Step 4: Add Waste Percentage
Multiply your cubic yards by 1.05 (for 5% waste) or 1.10 (for 10% waste). This accounts for spillage, uneven ground, and measurement variations.
Example Calculation:
Driveway: 20ft long × 10ft wide × 4in deep
- Convert depth: 4 inches ÷ 12 = 0.33 feet
- Calculate volume: 20 × 10 × 0.33 = 66.67 ft³
- Convert to yards: 66.67 ÷ 27 = 2.47 yd³
- Add 10% waste: 2.47 × 1.10 = 2.72 yd³
- Order: 2.72 cubic yards (round up to 3 yards)
Our concrete slab calculator automates these calculations and provides instant results. Simply enter your dimensions and get accurate cubic yard estimates with waste included.
Should I Use Bags or Ready-Mix Concrete?
Choosing between bagged concrete and ready-mix delivery depends on your project size, budget, timeline, and physical capability. Here's a detailed comparison:
| Factor | Bagged Concrete | Ready-Mix |
|---|---|---|
| Best For | Under 1 cubic yard | Over 2 cubic yards ✅ |
| Cost per Yard | $180-$270 | $125-$150 ✅ |
| Labor Required | High - mixing required ⚠️ | Low - ready to pour ✅ |
| Quality Consistency | Variable - depends on mixing | Excellent - factory mixed ✅ |
| Timeline | Flexible - work at your pace | Tight - must pour quickly ⚠️ |
| Minimum Order | None - buy what you need ✅ | Often 1 yard minimum |
| Delivery Fees | None ✅ | $50-$150 for small loads |
| Strength | Good if mixed properly | Excellent - precise ratios ✅ |
✅ Use Bagged Concrete When:
- • Project is under 1 cubic yard (27 bags)
- • Working on small repairs or patches
- • No truck access to site
- • Working at your own pace over multiple days
- • Budget allows for higher per-yard cost
- • Setting fence posts or small footings
✅ Use Ready-Mix When:
- • Project is over 2 cubic yards
- • Pouring driveways, patios, or foundations
- • Truck can access the site
- • Want consistent, professional quality
- • Have crew ready to pour quickly
- • Need specific mix specifications
The 1-2 Yard Gray Zone: For projects between 1-2 cubic yards, consider your physical capability (45-90 bags is heavy work), timeline, and whether you have help. Ready-mix is usually worth it for the time savings and quality assurance.
How Thick Should a Concrete Slab Be?
Concrete thickness is critical for structural integrity and longevity. Too thin and it will crack; too thick wastes money. Here are industry-standard thickness recommendations:
Residential Applications
- • Sidewalks: 4 inches minimum
- • Patios: 4 inches (light use)
- • Driveways: 4-6 inches (cars)
- • Garage floors: 4-6 inches
- • Shed pads: 4 inches
- • RV pads: 6-8 inches (heavy vehicles)
Commercial/Heavy-Duty
- • Commercial driveways: 6-8 inches
- • Parking lots: 6-8 inches
- • Loading docks: 8-12 inches
- • Foundation footings: 8-12 inches
- • Basement floors: 4-6 inches
- • Industrial floors: 6-12 inches
Important Factors Affecting Thickness:
- Soil conditions: Poor soil requires thicker slabs or additional base
- Load expectations: Heavier vehicles need thicker concrete
- Climate: Freeze-thaw cycles may require thicker slabs
- Reinforcement: Wire mesh or rebar can allow slightly thinner slabs
- Local codes: Always check building codes for minimum requirements
Cost vs. Thickness: Increasing thickness from 4 to 6 inches adds 50% more concrete cost but can double the lifespan and load capacity. For driveways, the extra 2 inches typically costs $200-$400 more but prevents premature cracking and failure.
Use our concrete calculator to see how thickness affects your total cubic yards and cost. Adjust the depth field to compare different thickness options for your project.
Concrete Volume Calculation Formula
Our calculator uses industry-standard formulas to determine concrete requirements accurately:
- Volume (ft³) = Length × Width × Depth
- Volume (yd³) = Volume (ft³) ÷ 27
- Bags (80lb) = Volume (yd³) × 45
- Total Cost = Volume (yd³) × Cost per Yard
Example: Residential Driveway Slab
For a standard driveway measuring 20ft × 10ft with 4-inch depth:
Example: Residential Driveway Slab
For a standard driveway measuring 20ft × 10ft with 4-inch depth:
Concrete Yardage Quick Reference Chart 2026
How many yards of concrete do you need? Use this quick reference for the most common project sizes at standard 4-inch depth.
| Project | Dimensions | Cubic Yards | 80lb Bags | Est. Cost |
|---|---|---|---|---|
| 10×10 Slab | 10ft × 10ft × 4in | 1.23 yd³ | 55 bags | ~$172 |
| 12×12 Patio | 12ft × 12ft × 4in | 1.78 yd³ | 80 bags | ~$249 |
| Driveway | 20ft × 10ft × 4in | 2.47 yd³ | 111 bags | ~$346 |
| 15×15 Patio | 15ft × 15ft × 4in | 2.78 yd³ | 125 bags | ~$389 |
| 20×20 Garage | 20ft × 20ft × 4in | 4.94 yd³ | 222 bags | ~$692 |
| 24×24 Garage | 24ft × 24ft × 4in | 7.11 yd³ | 320 bags | ~$995 |
| Sidewalk (50ft) | 50ft × 4ft × 4in | 2.47 yd³ | 111 bags | ~$346 |
Cost estimates based on $140/yd³ ready-mix. Add 10% for waste. Prices vary by region.
How to Calculate Concrete Yardage (Step-by-Step)
Here's exactly how to figure concrete yardage for any project:
Measure your dimensions in feet
Convert inches to feet: 4 inches = 0.333 ft, 6 inches = 0.5 ft, 8 inches = 0.667 ft
Calculate cubic feet
Cubic Feet = Length × Width × Depth (all in feet)
Convert to cubic yards
Cubic Yards = Cubic Feet ÷ 27 (there are 27 cubic feet in one cubic yard)
Add 10% for waste
Multiply your result by 1.10. Always order extra — running short mid-pour is a costly mistake.
Example: 10×10 Slab at 4 Inches
Step 1: Depth = 4 ÷ 12 = 0.333 ft
Step 2: Cubic Feet = 10 × 10 × 0.333 = 33.3 ft³
Step 3: Cubic Yards = 33.3 ÷ 27 = 1.23 yd³
Step 4: With waste = 1.23 × 1.10 = 1.35 yd³ to order
Concrete Cost Per Yard 2026 — What to Expect
Concrete prices vary by region, mix type, and delivery distance. Here's what you can expect to pay in 2026:
Ready-Mix Concrete (Delivered)
- • Standard mix: $125–$150/yd³
- • High-strength (4000+ PSI): $150–$175/yd³
- • Fiber-reinforced: $140–$165/yd³
- • Colored concrete: $150–$200/yd³
- • Small load fee (<5 yd³): +$50–$150
Bagged Concrete Mix
- • 80lb bag: $5–$7 each
- • 60lb bag: $4–$6 each
- • Cost per cubic yard: $225–$315
- • 45 bags (80lb) = 1 cubic yard
- • Best for projects under 1 yd³
Money-Saving Tip
For projects over 2 cubic yards, ready-mix is almost always cheaper than bags. Get quotes from 2-3 local suppliers — prices can vary by $20-30/yard in the same area.
Frequently Asked Questions
How much concrete do I need?
To calculate concrete needed: (1) Measure length, width, and depth of your project, (2) Calculate volume (length × width × depth), (3) Convert to cubic yards by dividing by 27. Our calculator does this automatically. For a 10ft × 10ft slab at 4 inches deep, you need approximately 1.23 cubic yards.
How many yards of concrete do I need?
Cubic yards = (Length × Width × Depth in feet) ÷ 27. For example, a 20ft × 10ft × 4in (0.33ft) slab needs 2.47 cubic yards. Always order 5-10% extra to account for waste, spillage, and uneven ground.
How much does a yard of concrete cost?
Concrete costs typically range from $125-$150 per cubic yard for standard mix, delivered. Prices vary by location, delivery distance, and mix specifications. High-strength or specialty mixes can cost $150-$200 per yard. Small loads under 10 yards often incur additional fees.
How many bags of concrete per yard?
One cubic yard of concrete equals approximately 45 bags of 80lb concrete mix, or 60 bags of 60lb mix. For small projects under 1 cubic yard, bags are convenient. For larger projects over 2 cubic yards, ready-mix delivery is more cost-effective and ensures consistent quality.
How thick should a concrete slab be?
Residential driveways and patios: 4 inches minimum. Garage floors: 4-6 inches. Driveways for heavy vehicles: 5-6 inches. Sidewalks: 4 inches. Foundation footings: 8-12 inches. Always check local building codes for specific requirements in your area.
Should I use bags or ready-mix concrete?
Use bags for projects under 1 cubic yard (27 bags or less) - convenient but labor-intensive. Use ready-mix for projects over 2 cubic yards - more cost-effective, consistent quality, and faster. For 1-2 cubic yards, consider your budget, timeline, and physical capability.
How do I calculate concrete for a circular slab?
For circular slabs: Volume = π × radius² × depth. Convert radius to feet, depth to feet (4 inches = 0.33 ft), then divide by 27 for cubic yards. Example: 10ft diameter (5ft radius), 4in deep = 3.14 × 25 × 0.33 ÷ 27 = 0.96 cubic yards.
What is the difference between concrete and cement?
Cement is an ingredient in concrete, not the same thing. Concrete is a mixture of cement (10-15%), water, sand, and gravel/aggregate. Cement acts as the binding agent. You cannot use cement alone for construction - you need the complete concrete mix for structural strength.
How long does concrete take to cure?
Concrete reaches 70% strength in 7 days, 90% in 28 days, and full strength in 90 days. You can walk on it after 24-48 hours, drive on it after 7 days, but wait 28 days before heavy loads. Keep it moist for the first 7 days for optimal curing and strength.
How do I calculate concrete yardage?
Concrete yardage formula: Cubic Yards = (Length × Width × Depth in feet) ÷ 27. Convert depth from inches to feet first (divide by 12). Example: 15ft × 15ft × 4in slab = (15 × 15 × 0.333) ÷ 27 = 2.78 cubic yards. Always add 10% for waste.
How much concrete do I need for a 10x10 slab?
A 10×10 slab at 4 inches thick needs 1.23 cubic yards or about 55 bags of 80lb concrete mix. At 6 inches thick, you need 1.85 cubic yards or 83 bags. At $140/yard for ready-mix, a 4-inch 10×10 slab costs approximately $172 in materials.
How do I figure concrete in cubic yards?
Step 1: Measure length, width, and depth in feet (convert inches to feet by dividing by 12). Step 2: Multiply all three: Volume (ft³) = L × W × D. Step 3: Divide by 27 to get cubic yards. Step 4: Add 10% for waste. This calculator does all steps automatically.
What does a yard of concrete cover?
One cubic yard of concrete covers: 81 sq ft at 4 inches thick, 54 sq ft at 6 inches thick, 40.5 sq ft at 8 inches thick. For a standard 4-inch residential slab, one yard covers roughly a 9×9 foot area. Use this calculator to find exact coverage for your dimensions.
How much does 5 yards of concrete cost?
At average prices of $125-$150 per cubic yard, 5 yards of ready-mix concrete costs $625-$750 for materials. Add delivery fees ($50-$150), labor ($2-$5 per sq ft), and finishing costs. Total installed cost for 5 yards is typically $1,500-$3,000 depending on your location.
How do I estimate concrete for a patio?
For a patio: measure length × width in feet, multiply by depth in feet (4 inches = 0.333 ft), divide by 27 for cubic yards. A 12×12 patio at 4 inches = (12 × 12 × 0.333) ÷ 27 = 1.78 cubic yards. Add 10% waste = 1.96 yards. At $140/yard = ~$274 in concrete.
📚 Related Concrete Guides
Explore our comprehensive concrete guides for specific projects and detailed information:
Concrete for 10x10 Slab
Exact yards and bags needed for a 10×10 slab at different thicknesses
Read Guide →How Much Concrete Do I Need?
Complete step-by-step calculation guide with formulas and examples
Read Guide →Concrete Cost Per Yard
2026 pricing guide with cost breakdowns and money-saving tips
Read Guide →