Enter the volume of concrete needed
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/bagDefault: $3.98/bag
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/bagDefault: $5.48/bag
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/bagDefault: $6.98/bag
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/bagDefault: $7.98/bag
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/CYDefault: $137.00/CY
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flatDefault: $175.00flat
Learn more with these helpful guides and tips
Choosing the right concrete bag size makes the difference between a smooth DIY project and unnecessary heavy lifting. Whether you're setting fence posts, pouring a small slab, or repairing concrete, understanding bag yields, costs per cubic foot, and total project requirements ensures you buy exactly what you need without multiple store trips or wasted materials.
Bagged concrete comes in four standard sizes: 40lb, 60lb, 80lb, and 90lb bags. Each size has specific advantages depending on your project scale, physical capability, and budget. This comprehensive guide breaks down everything you need to know to make the smartest choice for your concrete project.
Standard Bag Yields:
• 40lb bag = 0.30 cubic feet
• 60lb bag = 0.45 cubic feet
• 80lb bag = 0.60 cubic feet
• 90lb bag = 0.68 cubic feet
| Bag Size | Yield (CF) | Bags per CY | Best For | Typical Price |
|---|---|---|---|---|
| 40lb | 0.30 | 90 | Small repairs, single posts | $3.50-4.50 |
| 60lb | 0.45 | 60 | Multiple posts, small projects | $4.00-5.00 |
| 80lb | 0.60 | 45 | Medium projects, most popular | $4.50-5.50 |
| 90lb | 0.68 | 40 | Large projects, experienced DIYers | $5.00-6.00 |
The 80lb bag is America's most popular concrete bag size, offering the best balance between manageability, yield, and cost per cubic foot. For most DIY projects under 2 cubic yards, 80lb bags provide the optimal combination of convenience and value.
40lb Bags - The Light Option:
Perfect for small repairs, single fence posts, or projects where you need to carry bags long distances. At just 40 pounds, these bags are manageable for most people working alone. However, you'll need three 40lb bags to equal two 60lb bags, which means more mixing and potentially higher overall cost.
60lb Bags - The Middle Ground:
Ideal for setting multiple posts, mailbox installations, or small concrete pours. The 60lb size strikes a balance for those who find 80lb bags too heavy but want better efficiency than 40lb bags. Popular choice for older DIYers or those with physical limitations.
80lb Bags - The Standard:
The industry standard and most cost-effective option per cubic foot. If you can comfortably lift 80 pounds, this size minimizes mixing batches, reduces waste, and typically offers the best price point. Use these for slabs up to 50 square feet, setting deck posts, or any project requiring 0.5-2 cubic yards.
90lb Bags - The Heavy Hitter:
Best for experienced contractors or large DIY projects where minimizing bag count matters. The weight difference from 80lb bags is noticeable, but you'll need 10% fewer bags overall. Consider these only if you're comfortable with heavy lifting and have help available.
Calculating concrete bags requires knowing your project volume in cubic feet or cubic yards. Use this straightforward process:
For a 10×10 foot slab at 4 inches thick:
• Volume: 10 × 10 × 0.33 = 33 cubic feet
• With waste: 33 × 1.10 = 36.3 cubic feet
• Using 80lb bags: 36.3 ÷ 0.60 = 60.5 → 61 bags needed
• Total cost: 61 × $5.00 = $305
The decision between bagged concrete and ready-mix delivery typically breaks even around 1 cubic yard (27 cubic feet). Here's the math:
For 1 Cubic Yard:
Ready-Mix Delivery:
Beyond the monetary cost, consider that mixing 45 bags of concrete is physically demanding work. Each bag requires hauling, opening, mixing with water, and pouring. For projects over 1 cubic yard, ready-mix isn't just cost-competitive—it's dramatically less exhausting and produces more consistent results.
For projects requiring more than 5-10 bags, rent a portable cement mixer ($50-75/day). Hand-mixing is feasible for very small projects but becomes impractical quickly. Other essential tools include:
Step 1: Prepare Your Work Area
Set up near your pour location. Concrete begins setting within 30-45 minutes in warm weather, so minimize transport distance. Have all tools ready and forms prepared before mixing your first bag.
Step 2: Add Water Carefully
Start with 75% of the recommended water (listed on bag). For an 80lb bag, that's typically 2-2.5 quarts to start. Mix thoroughly, then add water gradually until reaching the desired consistency.
Never add too much water. Excess water reduces concrete strength by 20-30%. The mix should be thick enough to hold its shape but wet enough to flow smoothly. Think peanut butter consistency, not pancake batter.
Step 3: Mix Thoroughly
Whether machine or hand mixing, ensure no dry pockets remain. Mix for at least 3-5 minutes in a mixer, or until color is consistent throughout. Scrape sides and bottom of mixer or wheelbarrow to incorporate all dry material.
Step 4: Use Immediately
Pour and finish within 20-30 minutes of mixing. If concrete begins to stiffen in your mixer or wheelbarrow, do not add more water—this creates weak concrete. Instead, work faster or mix smaller batches.
While larger bags cost more per bag, they're cheaper per cubic foot of concrete. Here's the breakdown based on typical retail prices:
| Bag Size | Price | Yield (CF) | Cost per CF | Value Rating |
|---|---|---|---|---|
| 40lb | $4.00 | 0.30 | $13.33 | ★★☆☆☆ |
| 60lb | $4.50 | 0.45 | $10.00 | ★★★☆☆ |
| 80lb | $5.00 | 0.60 | $8.33 | ★★★★★ |
| 90lb | $5.50 | 0.68 | $8.09 | ★★★★☆ |
The 80lb bag offers the best value for most DIYers. While 90lb bags are marginally cheaper per cubic foot, the extra weight makes them impractical unless you're young, fit, and working with help.
Buy in Bulk During Sales:
Major home improvement stores run concrete sales during spring and summer. Bagged concrete has a long shelf life (1-2 years if stored properly), making it safe to stock up. Look for 20-30% off sales, typically around Memorial Day, July 4th, and Labor Day.
Store Bags Properly:
Keep unused bags in a dry location, elevated off concrete floors. Stack on pallets or 2×4s with plastic sheeting underneath and covering. Properly stored bags remain usable for months, perfect for staged projects or future repairs.
Calculate Accurately:
Over-buying bags is expensive waste. Under-buying means emergency store trips and potential cold joints in your concrete. Use our calculator above to get precise quantities, then add just 10% for safety.
This is the #1 mistake that ruins DIY concrete projects. Wet concrete is easier to mix and pour, but excess water creates weak concrete that crumbles within months. Follow the water recommendations on the bag, and when in doubt, mix it stiffer.
Concrete doesn't wait. If your project requires more than 15-20 bags, you need help. One person mixing while another pours and finishes keeps concrete fresh and prevents hardening before placement. Solo projects should stay under 10 bags maximum.
Concrete chemistry is temperature-sensitive. Below 50°F, curing slows dramatically. Above 85°F, concrete sets too quickly for proper finishing. Ideal temperature range is 60-75°F. If working in heat, mix smaller batches and work quickly.
For hot weather concrete work: chill your mixing water, wet down the forms and subgrade before pouring, and cover finished concrete immediately with damp burlap or plastic sheeting to slow evaporation.
Concrete poured over loose dirt, vegetation, or soft soil will crack and sink. Always excavate to firm subgrade, compact thoroughly, and add 4 inches of gravel base for slabs. For post holes, compact the bottom before setting posts.
Empty concrete bags, excess mix, and mixer washout create disposal challenges. Set aside an area for hardened concrete waste (it can be broken up and used as fill), and plan bag disposal. Most landfills accept empty bags, but check local regulations.
Use our free Concrete Bags Calculator above to instantly compare 40lb, 60lb, 80lb, and 90lb bag options. Get accurate quantities and cost comparisons for your specific project volume in seconds.
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