Concrete Calculator
Understanding Concrete Calculations
Concrete is sold by volume (cubic yards in the US, cubic meters internationally). To determine how much you need, calculate the volume of your project and add 10-15% for waste and variations.
Common Concrete Projects
- Slabs: Patios, driveways, walkways, garage floors
- Columns: Support posts, decorative pillars, fence posts
- Tubes: Hollow columns, planters, architectural features
- Stairs: Steps, retaining walls, terraced landscaping
Concrete Bag Sizes and Coverage
| Bag Size | Coverage | Best For |
|---|---|---|
| 40 lbs | 0.011 cubic yards | Small repairs, posts |
| 60 lbs | 0.017 cubic yards | Medium projects |
| 80 lbs | 0.022 cubic yards | Large projects (most efficient) |
Concrete Thickness Guidelines
Proper thickness is crucial for durability. Too thin, and your concrete will crack. Here are standard thicknesses for common applications:
- Sidewalks: 4 inches minimum
- Patios: 4 inches (6 inches if vehicles may drive on it)
- Driveways: 6 inches (8 inches for heavy trucks)
- Garage slabs: 6 inches minimum
- Basement floors: 4-6 inches depending on soil conditions
Planning Your Concrete Pour
Success depends on proper planning. Consider these factors before you start:
- Weather: Avoid extreme temperatures and precipitation
- Access: How will you get concrete to the pour location?
- Tools: Have all tools ready before mixing begins
- Help: Concrete work is time-sensitive; have enough people
- Finishing: Plan your finishing technique in advance
Cost Factors
Concrete costs vary by location, supplier, and quantity. Factors affecting price include:
- Bag vs. Ready-mix: Ready-mix is more cost-effective for large projects (> 2 cubic yards)
- Delivery: Factor in delivery fees for ready-mix concrete
- Special mixes: High-strength, colored, or fast-setting concrete costs more
- Tools: Budget for tools and equipment if you don't own them
- Labor: Professional installation typically costs $3-7 per square foot
Frequently Asked Questions
How much does a yard of concrete weigh?
A cubic yard of concrete typically weighs between 3,000 to 4,000 pounds (1.5 to 2 tons), depending on the mix design and aggregate used. Standard concrete averages about 3,700 pounds per cubic yard.
How many 80-pound bags equal one cubic yard?
Approximately 45 bags of 80-pound concrete mix equal one cubic yard. However, this can vary slightly based on the specific mix and manufacturer. Always check the coverage information on your bag.
Should I buy 60-pound or 80-pound concrete bags?
80-pound bags are more efficient and cost-effective for larger projects, requiring fewer bags total. 60-pound bags are easier to handle if you‘re working alone or have physical limitations. For small repairs, 40-pound bags work well.
How thick should a concrete slab be?
For residential walkways: 4 inches minimum. For driveways and patios: 4-6 inches. For heavy vehicle access: 6-8 inches. Commercial applications may require 8 inches or more. Always check local building codes.
How much extra concrete should I order?
Order 10-15% extra concrete to account for waste, spillage, uneven subgrade, and slight variations in thickness. For critical pours or complex shapes, consider 20% extra. It‘s cheaper to order too much than to run short.
What is the difference between concrete and cement?
Cement is just one ingredient in concrete. Concrete is made of cement, water, sand, and gravel (aggregate). Cement acts as the binding agent that holds everything together when it cures.
How long does concrete take to cure?
Concrete reaches initial set in 24-48 hours but continues curing for weeks. It reaches about 70% strength in 7 days and full strength (3,000-4,000 PSI) in 28 days. You can usually walk on it after 24 hours.
Can I mix my own concrete instead of buying bags?
Yes, you can mix portland cement, sand, gravel, and water. The typical ratio is 1:2:3 (cement:sand:gravel) by volume. However, bagged mixes are pre-proportioned and more convenient for small to medium projects.
What tools do I need for a concrete project?
Basic tools include: shovel or hoe for mixing, wheelbarrow, level, float, trowel, edger, and safety equipment (gloves, eye protection). For larger projects, consider renting a concrete mixer.
When is the best time to pour concrete?
Pour concrete when temperatures are between 50°F and 90°F (10°C to 32°C). Avoid extremely hot, cold, or windy days. Don‘t pour in rain or when rain is expected within 24 hours.
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Prodotti Consigliati
Aggiornato Febbraio 2026 · Testati e verificati
Heavy Duty Wheelbarrow
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Durable wheelbarrow for transporting concrete and construction materials
Portable Concrete Mixer
Electric concrete mixer for small to medium concrete projects
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Safety Goggles with Side Protection
Essential eye protection for concrete mixing and construction work
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Heavy Duty Work Gloves
Protective work gloves for handling concrete and construction materials
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