Calculate exact concrete volume in cubic yards or meters, plus required 80lb, 60lb, or 50lb Quikrete premix bags for slabs, walkways, and post footings.
📐 Slab Dimensions
📦 Material Requirements
1.63 yd³
44.0 Cubic Feet (with 10% waste)
Choose Your Premix Bag Size:
74
80 lb (36 kg) Bags
0.60 cu ft yield
98
60 lb (27 kg) Bags
0.45 cu ft yield
Total Weight: 5,940 lbs (3.0 tons)Water Needed: ~55 gal
🚛 Ready-Mix Recommendation: At 1.63 cubic yards, you are right at the tipping point where ordering a ready-mix truck may cost less than buying 74 heavy bags and save you hours of physical labor!
🕳️ Cylinder Footing Dimensions
Example: 36 inches (3 feet deep)
📦 Post Footing Results
0.27 yd³
7.3 Cubic Feet Total
13
80 lb Bags Total
3.3 bags per post
17
60 lb Bags Total
4.3 bags per post
💡 Post Installation Tip: Use Fast-Setting Concrete (yellow bag) for fence posts. Pour dry mix straight into the hole around the plumb post, then pour water directly on top without pre-mixing in a wheelbarrow!
The Definitive Guide to Concrete Slab & Footing Estimation
Pouring a concrete patio, walkway, shed base, or deck footing requires precision when estimating volume. Underestimating your pour leaves you with a catastrophic "cold joint" when wet concrete cures before the next batch arrives. Overestimating leaves you with hundreds of pounds of useless hardened concrete.
Always include a 10% safety contingency for slabs. Subgrades are rarely laser flat; an extra 1/2 inch of grade depth across a 10x10 slab increases concrete volume requirements by over 12%.
Bags vs. Ready-Mix Truck Tipping Point
While bags are ideal for small footings and fence posts, a single cubic yard of concrete weighs roughly 4,000 lbs (2 tons). Mixing 45 to 60 bags by hand in a wheelbarrow or small paddle mixer takes hours and risks physical exhaustion. Most ready-mix batch plants offer short-load trucks with a 1-yard minimum delivery, providing superior compressive strength (3,500–4,000 PSI) with zero mixing labor.
Frequently Asked Questions
What thickness should a concrete patio or shed slab be?
For pedestrian walkways and patio furniture, a 4-inch thick slab reinforced with welded wire mesh or fiber-mesh is standard. For driveways or heavy tractor sheds, a 5-inch to 6-inch slab with 1/2-inch (#4) rebar grid is required.
How long does concrete take to cure before you can walk or drive on it?
Concrete achieves roughly 50% of its design strength in 3 to 7 days. You can safely walk on it after 24 to 48 hours. Light vehicle parking requires at least 7 days, and full compressive strength is achieved after 28 days of continuous curing.
How much water should be added per bag of concrete?
An 80 lb bag of standard concrete requires approximately 3.0 to 3.5 quarts (0.75 to 0.85 gallons) of clean water. Avoid adding too much water; soupy concrete is easier to trowel but permanently sacrifices compressive strength and causes surface cracking.