Concrete Calculator for Triangle

Triangle Concrete Volume Calculator

Calculated Results:

Area:

Total Volume (Cubic Yards):

Total Volume (Cubic Feet):

80lb Bags (Pre-mix):

Estimated Material Cost:

function calculateConcreteVolume() { var base = parseFloat(document.getElementById('triBase').value); var height = parseFloat(document.getElementById('triHeight').value); var thicknessInches = parseFloat(document.getElementById('triThickness').value); var costPerYard = parseFloat(document.getElementById('triCost').value); if (isNaN(base) || isNaN(height) || isNaN(thicknessInches) || base <= 0 || height <= 0 || thicknessInches 0) { var totalCost = volumeCuYd * costPerYard; document.getElementById('resTotalCost').innerText = '$' + totalCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); document.getElementById('costRow').style.display = 'flex'; } else { document.getElementById('costRow').style.display = 'none'; } document.getElementById('concreteResult').style.display = 'block'; }

How to Calculate Concrete for a Triangular Slab

Calculating the amount of concrete needed for a triangular area (such as a corner patio, a wedge-shaped footing, or a decorative garden feature) involves determining the surface area of the triangle and then multiplying it by the intended thickness of the slab.

The Triangle Concrete Formula

To find the volume manually, use the following steps:

• Step 1: Calculate Surface Area. The formula for the area of a triangle is (Base × Height) / 2. If your base is 10 feet and your height is 12 feet, your area is 60 square feet.
• Step 2: Convert Thickness to Feet. Since dimensions are usually in feet but thickness is in inches, divide the inches by 12. (e.g., 4 inches = 0.333 feet).
• Step 3: Calculate Cubic Feet. Multiply the Area (sq. ft.) by the Thickness (ft).
• Step 4: Convert to Cubic Yards. Most concrete suppliers sell by the yard. Divide your total cubic feet by 27 to get cubic yards.

Example Calculation

Imagine you are pouring a triangular corner for a shed base:

– Base: 8 feet
– Height: 6 feet
– Thickness: 4 inches

1. Area = (8 * 6) / 2 = 24 sq. ft.
2. Volume in Cubic Feet = 24 * (4 / 12) = 8 cubic feet.
3. Volume in Cubic Yards = 8 / 27 = 0.296 cubic yards.

The 10% Rule for Overage

When ordering ready-mix concrete, it is a standard industry practice to add 10% to your final total. This accounts for variations in the subgrade depth, slight spreading of the forms, or spills during the pour. It is much cheaper to have a small amount of concrete left over than to pay a "short-load" fee for a second delivery of only 0.25 yards.

Estimating Pre-Mixed Bags

If you are mixing the concrete yourself using bags, remember that a standard 80lb bag of high-strength concrete mix yields approximately 0.6 cubic feet when wet. To find the number of bags needed, divide your total cubic feet by 0.6 and round up to the nearest whole bag.