Concrete Calculator gives you precise concrete estimates for slabs, walls, footings, and columns
faster and more detailed than basic tools.
It instantly calculates volume, bag count, and total project cost
all in one free, easy-to-use interface.
Here you’ll also find clear formulas, mix ratios (1:2:4),
and expert tips to plan your concrete work accurately.
How to Use the Concrete Calculator
Estimate how much concrete you need for a project in minutes. This concrete calculator for slab, wall, footing, and round column outputs volume in cubic feet or yard of concrete and gives you the bag count and cost.
- Enter dimensions: Length × Width × Thickness (for concrete calculator slab) or the fields shown for wall/footing/column.
- Select your unit system: ft, inch, yard, or m. The tool converts to cubic yards for easy ordering.
- Choose the mode: Slab, Wall, Footing, or Round Column to match the shape you’re pouring.
- Click Convert to see total volume, yards of concrete, required bags, and—if needed—estimated cost.
🔎 Tip: Need a quick check? Enter slab size and thickness—the concrete calculator for slab returns both cubic feet and cubic yards for ordering.
Results include volume by unit, how much concrete in yards, and optional bag/cost estimates so you can plan materials precisely.
Concrete Volume & Bags Calculation
The calculator finds slab, wall, footing, or column volume first, then converts it to cubic yards for ordering and to bags of concrete for DIY projects. This doubles as a concrete bags calculator / bag concrete calculator.
🔢 Volume formula (rectangular slab):
Volume = Length × Width × Thickness
The tool supports instant unit conversion, reporting cubic feet ↔ cubic yards ↔ cubic meters.
📏 Helpful conversions
- 1 yd³ = 27 ft³
- 1 m³ ≈ 35.3147 ft³ ≈ 1.30795 yd³
- Thickness in inches → divide by 12 to get feet
🧱 Bags calculation:
Bags = Total volume (ft³) ÷ Volume per bag (ft³/bag)
Typical bag yields (approx.): 40 lb ≈ 0.30 ft³, 60 lb ≈ 0.45 ft³, 80 lb ≈ 0.60 ft³.
The concrete bag size you choose determines the final count of bags of concrete.
Example
12 × 10 × 4 inches slab ⇒ Volume ≈ 3.11 yd³ → about 140 bags of 80 lb concrete.
The tool also reports the same volume in ft³/m³ and shows concrete calculator yard results for ordering.
Results summarize cubic yards, yards of concrete to order, and precise bag counts—making this both a volume tool and a bags of concrete calculator.
Concrete Mix & Ratio Calculator (1:2:4 Mix Example)
The concrete mix calculator helps you find the right proportions of cement, sand, and gravel for different strength levels.
A 1:2:4 concrete mix means one part cement, two parts sand, and four parts gravel — a standard ratio for general construction projects around 20 MPa strength.
⚙️ How it works:
Enter the total concrete volume or number of bags, and the calculator shows how much cement, sand, and gravel are needed for your chosen ratio.
This feature acts as both a sand and cement calculator and a concrete mix calculator (sand, gravel, cement), making it easy to plan your materials precisely.
| Mix Type | Cement | Sand | Gravel | Strength |
|---|---|---|---|---|
| 1 : 2 : 4 | 1 | 2 | 4 | ≈ 20 MPa |
| 1 : 1.5 : 3 | 1 | 1.5 | 3 | ≈ 25 MPa |
💡 Tip: Adjusting the cement : sand : gravel ratio changes the concrete’s strength and workability — ideal for optimizing slabs, driveways, or structural foundations.
Concrete Cost Estimator (Bags & Total Price)
The concrete cost estimator calculates your total project price automatically. Once the calculator determines your required volume and bag count, it multiplies the number of bags × bag price, adds optional Tax% and Fees, and gives a final total in your chosen currency.
💲 Automatic cost breakdown:
- Bags × Price per bag = Material cost
- + Tax% (sales or regional tax, optional)
- + Fees (delivery, mixing, or handling costs)
- = Total project cost in USD or selected currency
This mode acts as a concrete price calculator or concrete calculator cost tool, showing the average cost of concrete per yard and nearby pricing variations (like concrete price calculator near me).
Example Calculation
3.25 yd³ → 146 bags × $5.25 = $816.20 including tax and fees.
The calculator automatically updates totals when you change bag price, tax rate, or currency.
💡 Use this concrete calculator cost estimator to budget materials accurately, compare suppliers, and plan your project with full transparency.
Discover More Free Calculators
Explore a full range of measurement, conversion, and math tools — all designed with accuracy and simplicity in mind.
From area and ratio converters to construction and finance tools, everything is just one click away.
FAQs – Concrete Cost & Coverage
How much does a 20×20 slab of concrete cost?
For a 4-inch thick slab: Area = 20 × 20 = 400 ft² → Thickness = 4″ = 0.333 ft → Volume = 400 × 0.333 ≈ 133.3 ft³ = 4.94 yd³.
Multiply cubic yards by your local price per yard to estimate total cost, or let the calculator do it automatically.
How much would a 40×60 concrete slab cost?
For a 4-inch slab: Area = 40 × 60 = 2,400 ft² → Volume = 2,400 × 0.333 ≈ 800 ft³ = 29.63 yd³.
Use the built-in Concrete Cost Estimator to find total price including tax and fees.
How much does a 30×30 concrete slab cost?
Area = 30 × 30 = 900 ft² → Volume = 900 × 0.333 ≈ 300 ft³ = 11.11 yd³.
Multiply by the cost per cubic yard to estimate your total project price.
How much is a yard of concrete in NC?
Concrete prices vary by region and supplier. Enter your price per yard in the calculator to see total cost for your North Carolina project, including tax and delivery.
How do I calculate how much concrete I need?
Use the formula: Volume = Length × Width × Thickness.
Convert cubic feet to cubic yards by dividing by 27, or simply enter dimensions in the Concrete Calculator for instant results.
What is the 20/30/40 rule in concrete?
The 20/30/40 rule refers to typical strength or mix ratios used in general concrete design — for example, 20 MPa (1:2:4), 30 MPa (1:1.5:3), and 40 MPa (1:1:2).
These indicate proportions of cement : sand : gravel in the mix.
How much will 10 yards of concrete cover 4 inches thick?
Each cubic yard covers about 81 ft² at 4 inches thick.
So, 10 yd³ × 81 ft² = approximately 810 ft² of surface area.
Is there an app to calculate how much concrete I need?
Yes — the Concrete Calculator on PixelsCalculator works as a free web app that estimates volume, bags, and total cost for any slab, wall, or footing.
It’s mobile-friendly and designed for contractors, homeowners, and DIY builders.
📘 For more information about concrete mixing and proportions, visit
Wikipedia – Concrete.