Concrete Calculator

concrete calculator triangle/Circle

Enter dimensions to calculate volume, weight and material quantities

Units & Grade

Shape

Dimensions

m
m
m

Wastage Buffer

7%

Accounts for spillage, overpouring, and formwork loss

Please enter valid positive values in all required fields.
Calculation complete
—
m³
Net Volume
—
m³
Order Volume (incl. wastage)
—
tonnes
Approximate Weight
—
× 50 kg bags
Equivalent Premix Bags
MaterialMix RatioQuantity Required
Formula Used
Rectangle: V = L × W × D   |   Circle: V = π/4 × D² × Depth   |   Triangle: V = ½ × L × W × D
Note: Guide only. Site conditions, formwork losses and rebar displacement may affect final quantities.

What Is a Concrete Calculator For Triangle?

A concrete calculator takes the guesswork out of your project. Enter your dimensions like length, width, and thickness, and it instantly tells you how much concrete you need. Whether you’re pouring a rentangle, circle or right triangle, this tool gives you a fast, accurate volume estimate in cubic yards or cubic feet.

How It Works

The calculator uses a simple volume formula:

Volume = Length × Width × Thickness

For slabs, walls, and footings, it converts your measurements into cubic yards, the standard unit ready-mix concrete suppliers use across the USA and Australia.

Want a triangle shape? Use the concrete triangle calculator mode. It handles non-rectangular areas with the same accuracy.

What You Can Calculate

  • Concrete volume (cubic yards / cubic feet)
  • Material weight estimates
  • Ready-mix bag count (60 lb or 80 lb bags)
  • Cost estimates based on your local price
  • Mix ratios including 1:2:4 concrete mix
How do I calculate concrete thickness?

Typical slabs run 4 inches thick for driveways and 6 inches for heavy loads. Enter your desired thickness directly into the concrete thickness calculator field and it adjusts your total volume instantly.

 Volume = Length × Width × Thickness. For triangles: Volume = (Base × Height ÷ 2) × Thickness. The calculator applies the right formula based on your shape.

 Yes. Switch to triangle mode, enter your base and height, and the concrete triangle calculator does the rest.

Enter your project dimensions above. The calculator gives you an instant estimate in cubic yards or cubic feet with no manual math needed.

 Multiply length × width × depth (in feet), then divide by 27. That converts cubic feet to cubic yards. Our calculator handles this automatically.

Multiply length × width × thickness and ensure all in meters. That gives you cubic meters (m³) directly. 

Example: 4m × 3m × 0.1m = 1.2 m³. Enter your dimensions above and the calculator does it instantly.

 One 20kg bag yields roughly 0.009 m³ (about 9 liters) of mixed concrete. For a 100mm thick slab, that covers approximately 0.09 m² of surface area. Small jobs only because larger pours need ready-mix.

 In the USA, ready-mix concrete typically runs $125–$200 per cubic yard. In Australia, expect $200–$350 AUD per m³ depending on your region, mix strength, and supplier. Always get a local quote because the prices vary by location and delivery distance.

One 20kg bag makes approximately 0.009 m³ of concrete. So to fill 1 full cubic meter, you’d need around 110 bags of 20kg premixed concrete. This is why ready-mix is preferred for any slab larger than a small pad.

Divide your total volume (in m³) by 0.009. For example, 0.5 m³ ÷ 0.009 = ~56 bags. Use the calculator above to get your volume first, then apply this formula, or enter your dimensions and let the bag estimator do the math.

 A 25kg bag of cement (not premix) covers roughly 0.011 m³ when mixed in a standard 1:2:4 ratio. Coverage varies based on your mix design and aggregate size. For precise material breakdowns, use the mix ratio calculator mode.

It depends on the application:

  • Foot traffic / pathways — 3 to 4 inches (75–100mm)
  • Residential driveways — 4 inches (100mm)
  • Heavy vehicle loads — 6 inches (150mm)
  • Structural slabs — 6–8 inches (150–200mm)

Thicker = stronger. Never go below 3 inches for any poured slab.

For a standard residential driveway, 4 inches (100mm) is the minimum. If you park heavy trucks, RVs, or machinery on it, go 5–6 inches (125–150mm). Always add a compacted gravel base underneath for drainage and long-term strength.

 Use your mix ratio to work backward from total volume. For a 1:2:4 mix:

  • Total parts = 1 + 2 + 4 = 7
  • Cement portion = Volume × (1 ÷ 7)

Example: For 1 m³ of concrete → cement needed = ~0.143 m³ (roughly 220–230 kg). The 1:2:4 mix calculator mode breaks this down automatically by material.

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