Concrete Cost Calculator
Calculate how much concrete costs for your project. Get instant estimates for cubic yards, bags, and cost.
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How to Calculate Concrete
Calculating the right amount of concrete prevents waste and shortages. The basic formula for any rectangular shape is simple: Volume = Length × Width × Thickness.
Basic Formula
Volume (ft³) = Length (ft) × Width (ft) × Thickness (ft). Divide by 27 to convert to cubic yards.
Tips for Accurate Estimates
- Always add 5–10% extra for waste, spillage, and uneven surfaces.
- Measure twice — small errors in dimensions multiply quickly in volume.
- Convert all measurements to the same unit before calculating.
- For irregular shapes, break the area into simple rectangles and add them up.
- Order slightly more ready-mix than calculated — running short during a pour is costly.
Bags vs. Ready-Mix
Bagged concrete (40–80 lb bags) is practical for small projects under 1 cubic yard. For larger pours, ready-mix delivery ($125–$165/yd³) is more cost-effective and ensures consistent quality.
Frequently Asked Questions
How much does concrete cost per cubic yard?
Ready-mix concrete typically costs $125 to $165 per cubic yard in the US (2026 prices). Prices vary by region, concrete mix type (PSI rating), and delivery distance. Short-load fees may apply for orders under 10 cubic yards.
How many bags of concrete do I need?
It depends on your project volume. An 80 lb bag covers about 0.6 cubic feet, a 60 lb bag covers 0.45 ft³, and a 40 lb bag covers 0.30 ft³. Use our calculators above to get exact bag counts for your dimensions.
What is the difference between concrete and cement?
Cement is a powder ingredient (Portland cement) that acts as a binder. Concrete is the finished product made by mixing cement with sand, gravel (aggregate), and water. Think of cement as flour and concrete as bread.
How long does concrete take to cure?
Concrete reaches about 70% strength in 7 days and full design strength in 28 days. Keep it moist during the first week for proper curing. You can walk on it after 24–48 hours, but avoid heavy loads for at least 7 days.
How thick should a concrete slab be?
Standard residential slabs (patios, sidewalks) are 4 inches thick. Driveways need 5–6 inches. Garage floors typically require 5–6 inches. Heavy-duty commercial applications may need 6–8 inches or more.
Can I pour concrete in the rain?
Light drizzle is usually fine if you can cover the fresh pour with plastic sheeting. Heavy rain can wash out cement paste and weaken the surface. Check the forecast and avoid pouring if rain is expected within the first 4–8 hours.
Do I need a permit for concrete work?
It depends on your location and the scope of work. Most jurisdictions require permits for structural work like foundations, retaining walls, and driveways. Simple projects like small patios or walkways often don't need permits. Always check with your local building department.
Should I use bags or order ready-mix concrete?
For projects under 1 cubic yard (about 27 cubic feet), bagged concrete is practical and gives you more control. For anything larger, ready-mix delivery is more cost-effective, faster, and provides consistent quality. The break-even point is typically around 1–2 cubic yards.