Australian Construction Calculators · 306 Tools
Construction estimates, with the maths shown.
Free, instant, Australian metric.
Concrete volumes. Roof tiles. Paint litres. Boiler sizes. Every formula is shown, every number is editable, and nothing leaves your browser.
Plan a whole job
Goes further than a single figure — set out a whole floor and see where every cut lands before you order.
Most-used calculators
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Concrete Slab Calculator
Calculates concrete volume for slabs, paths, and driveways
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Colorbond Roofing Calculator
Estimates metal roof panels, screws, and trim for standing seam and corrugated
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Paint Calculator
Calculates litres or gallons of paint for walls, ceilings, and trim
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Brick Calculator
Estimates bricks for walls
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Ceiling / Roof Insulation Calculator
Calculates rolls of mineral-wool ceiling insulation
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Home Extension Cost Calculator
Estimates build cost for extensions per m² or ft²
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View all →From the blog
All posts →-
Roofing Roof Batten Spacing and Quantities by Tile Type Roof batten spacing is derived from covering length and headlap, not chosen. This guide sets out the single lap and double lap formulas, a full worked example in metric with imperial equivalents, and the quantity method behind the calculator. -
Roofing What Does a New Roof Cost? A Breakdown Framework A new roof cost splits into five predictable lines: covering materials, labour, access, disposal and contingency. This post shows the geometry behind each one and works a full example in metric, with imperial equivalents throughout. -
Roofing How Many Roof Tiles Per Square Metre Roof tile counts come from batten gauge and cover width, not from tile size. This post sets out the formula, a full worked example on a 90.23 m² slope, and the wastage allowance to apply before ordering.
Estimates, not advice.
BuildMetricLab is a planning tool. Results are intended to help you scope a job and request quotes — they are not a substitute for a qualified trade quote, structural engineer's calculation, or National Construction Code (NCC) sign-off. Always verify with a professional before ordering materials or starting works.