Concrete Calculator

Calculate concrete volume for slabs, columns, walls, and footings.

calculators.concrete

descriptions.concrete

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Calculate concrete for multiple identical sections

Cubic Yards
1.23
yd³
Cubic Feet
33.3
ft³
Cubic Meters
0.94
+10% Waste
1.36
yd³
Bags Needed
40lb bags112
60lb bags75
80lb bags56
Cost Estimates
Ready-mix ($125/yd³)${(cubicYards * 125).toFixed(0)}
Premium ($150/yd³)${(cubicYards * 150).toFixed(0)}
Bagged (80lb @ $5)${(bags80lb * 5).toFixed(0)}
w/ 10% waste${((cubicYards * 1.1) * 125).toFixed(0)}
Quick Reference
Weight4938 lbs
Truck loads1 (10yd³ ea)
Wheelbarrows6 (6ft³ ea)
Mix time~224 min
10' × 10' 4"1.23 yd³
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Enter dimensions to calculate concrete volume in cubic yards, cubic feet, and bags needed. Choose your project type (slab, column, wall, or footing) for accurate results.

Standard Mix Ratio (1:2:3)

🪨
1
Cement
🏖️
2
Sand
🪨
3
Gravel
💧
0.5
Water

PSI Strength Levels: 2500-3000 (residential), 3500-4000 (commercial), 4500+ (structural)

28-Day Curing Timeline

Day 1
Initial Set
~20% strength
Day 3
Light Use
~40% strength
Day 7
Foot Traffic
~70% strength
Day 14
Vehicle OK
~85% strength
Day 28
Full Cure
100% strength

Critical: Keep moist for first 7 days. Avoid heavy loads for 7+ days. Ideal temperature: 50-85°F.

Project Types

Slab/Floor: Patios, garage floors (4-6" thick)
Column/Post: Vertical cylinders for support
Wall: Retaining walls, foundations (6-8" thick)
Footing: Base support (12-24" deep)

Bag Coverage (4" thick)

40lb bag: 0.30 ft³ • ~0.9 sq ft
60lb bag: 0.45 ft³ • ~1.4 sq ft
80lb bag: 0.60 ft³ • ~1.8 sq ft
Bulk (1 yd³): 27 ft³ • ~81 sq ft

Common Project Estimates

10×10 Patio (4")
1.23 yd³
~56 bags (80lb)
20×20 Garage (6")
7.41 yd³
~333 bags (80lb)
12" Post (4')
0.13 yd³
~6 bags (80lb)
4×50 Sidewalk (4")
2.47 yd³
~111 bags (80lb)

Pro Tips

💡Order 10% extra concrete to account for waste and spillage
🚚For projects over 1 cubic yard, ready-mix is more economical than bags
⏱️1 cubic yard = 27 cubic feet = 45 bags of 80lb concrete
🌡️Always have proper forms and reinforcement ready before pour
📏Use rebar or wire mesh for slabs over 4". Improves crack resistance by 60%.
🏗️Add fiber reinforcement for driveways. Reduces shrinkage cracks and extends lifespan.

Frequently Asked Questions

How much concrete do I need for a 10x10 slab?

For a 10' × 10' slab at 4 inches thick, you'll need approximately 1.23 cubic yards or 56 bags of 80lb concrete mix. Always order 10% extra to account for waste and spillage.

Should I use bagged concrete or ready-mix?

For projects under 1 cubic yard, bagged concrete is convenient but labor-intensive. For anything over 1 cubic yard, ready-mix concrete delivered by truck is more cost-effective and ensures better quality and consistency.

How thick should a concrete slab be?

For residential applications, 4 inches is standard for patios and walkways. Garage floors and driveways should be 4-6 inches thick. For heavy loads or poor soil conditions, consult a structural engineer for proper thickness requirements.

How long does concrete take to cure?

Concrete typically reaches sufficient strength for foot traffic in 24-48 hours. However, full curing takes 28 days. Avoid heavy loads, vehicles, or construction for at least 7 days. Keep the concrete moist during the first week for optimal strength.

What PSI strength do I need?

Residential projects typically use 2500-3000 PSI concrete. Commercial applications require 3500-4000 PSI. Structural elements like foundations and columns need 4500+ PSI. Check local building codes for specific requirements.

Do I need rebar or wire mesh?

Yes, for most slabs over 4 inches thick. Rebar is best for driveways and structural slabs. Wire mesh works well for patios and walkways. Reinforcement reduces cracking by 60% and significantly extends the lifespan of your concrete.

What's the best time of year to pour concrete?

Spring and fall are ideal when temperatures are between 50-85°F. Avoid pouring in freezing temperatures or extreme heat. Hot weather causes rapid drying and cracking, while cold weather slows curing and reduces strength.

How do I calculate concrete for irregular shapes?

Break irregular shapes into rectangles, circles, or triangles. Calculate volume for each section separately, then add them together. For curved areas, measure the longest and widest points and multiply by 0.8 for an estimate.

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