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✦ Measurements

Concrete Calculator

Calculate slab, beam and column quantities in m³ or ft³. Enter feet and inch thickness, then estimate project costs from your own quote.

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Use your slab length, width and thickness. For example, feet for length/width and inches for thickness.

Length, width and diameter use the selected main unit. Choose a separate unit for thickness, depth or height. Changing shape or main unit clears the three measurements so old numbers cannot be mislabelled.

Examples are not recommendations. Use measurements from your own project.

Concrete project planner

Calculate each slab, beam or column above, then add it here. Different dimensions and m/ft units can share one project.

Up to 30 components. Each saved component retains its dimensions, count and allowance. Editing the calculator does not change saved components.

Your project is empty. Calculate a component above, then add its quantities here.

Allowances are included once per component. This sum does not combine mix grades or schedule separate pours. Budget uses one supplier rate for all components, plus one fixed charge; confirm delivery, minimum loads, pumping and taxes with your supplier. Material recipes above apply only to the current component.

How the estimate works

How the estimate works

Rectangular volume = length × width × height × count. Cylinder volume = π × (diameter / 2)² × height × count. Order volume = geometric volume × (1 + allowance / 100). The allowance is applied once.

Optional: dry ingredient volume = order volume × your dry factor. Each ingredient volume = dry volume × its ratio part / total ratio parts. Cement mass = loose cement volume × your loose bulk density; bags = mass / bag mass. Whole bags round upward. No water, sand mass or aggregate mass is inferred.

The geometry example is 5 × 4 × 0.15 m with 10% allowance: 3 m³ geometric and 3.3 m³ order volume. It is a teaching example, not a recommended allowance or structural design.

Common concrete questions

Can I calculate a slab in feet and inches?

Yes. Set the main unit to feet and the thickness unit to inches. Results are displayed in both m³ and ft³.

Does the calculator choose a concrete mix or allowance?

No. Allowance starts at 0%. Any material recipe must be supplied by you. Ask your supplier or engineer which mix is suitable.

How do I estimate concrete cost in Sri Lanka?

Add calculated components to the project below and enter your own supplier's LKR rate and any fixed charge. No live prices are assumed.

Unit reference: NIST international foot

Inputs are calculated locally in your browser.