All Calculators
The complete BuildFactor library — all 97 calculators across 19 categories are live, each with its formula, a worked example and cited sources. Filter by category or search.
Concrete · 12
Concrete Calculator
How much concrete a rectangular slab or footing needs, in cubic yards or cubic metres.
Sonotube Concrete Calculator
Concrete volume for round column forms (Sonotube-style tubes).
Concrete Calculator for Fence Posts
Concrete volume to set a run of fence posts, allowing for the posts displacing concrete in each hole.
Concrete Cost Calculator
Estimated material cost of a concrete pour from its volume and a unit price.
Roofing · 10
Roof Area Calculator
Sloped surface area of a simple gable or hip roof from its footprint and pitch.
Roof Shingle Calculator
Shingle bundles and roofing squares for a roof of a given surface area.
Tile & Flooring · 7
Tile Calculator
Tiles and boxes needed for a floor or wall, including an allowance for cuts.
Flooring Calculator
Flooring material (planks or boxes) for a room, including waste.
Landscaping & Driveway · 12
Cubic Yard Calculator
Convert a length, width and depth into cubic yards, cubic feet or cubic metres.
Gravel Calculator
Gravel by volume and by delivered weight for driveways, paths and fill.
Bituminous Prime & Tack Coat Calculator
Bituminous prime coat or tack coat material for a paved area from its application rate.
Masonry · 5
Plastering Calculator
Plaster (render) volume, plus cement bags and sand, for a wall or ceiling area from its thickness and mix ratio.
Lumber & Wood · 4
Board Foot Calculator
Board feet for a piece or a list of lumber from its dimensions.
Framing · 4
Door Header Size Calculator
Header size estimate for a door or window opening — an estimate, not an engineering design.
Floor Joist Calculator
Floor joist count and a span estimate — an estimate, not an engineering design.
Wood Beam Span Calculator
Allowable span estimate for a sawn-lumber beam under a uniform load — an estimate, not an engineering design.
Stairs · 3
Walls · 4
Drywall & Insulation · 3
Drywall Sheet Calculator
Sheet count only for a given wall or ceiling area and sheet size.
Insulation Calculator
Insulation coverage (batts or bags) for a wall, floor or attic area.
Painting · 4
Paint Coverage Calculator
Area a given amount of paint will cover, or paint needed for an area.
Siding · 2
Fencing · 2
Drainage · 1
French Drain Calculator
Gravel, pipe and fabric for a French drain of a given length and trench size.
Steel & Reinforcement · 1
Rebar Calculator
Rebar quantity, spacing and lineal feet for a slab or footing grid.
Materials · 16
Aggregate Specific Gravity & Water Absorption Calculator
Bulk (oven-dry and SSD), apparent specific gravity and water absorption of a coarse aggregate sample from its oven-dry, SSD and submerged mass.
Atterberg Limits Calculator
Liquid limit (one-point method), plastic limit and plasticity index of a fine-grained soil.
California Bearing Ratio (CBR) Calculator
California Bearing Ratio of a subgrade or base sample at 2.5 mm and 5.0 mm penetration, against the ASTM standard loads.
In-Situ Dry Density Calculator
Field bulk density, dry density and percent compaction of compacted soil from a drive-cylinder (core cutter) sample.
Water & Volume · 3
Pipe Volume Calculator
Volume of liquid a length of pipe holds from its diameter and length.
Tank Volume Calculator
Capacity of a tank — cylindrical, rectangular or oval — full or partly filled.
Accessibility · 1
Additional Construction · 3
Air Conditioner (BTU) Sizing Calculator
Estimated BTU/hr cooling capacity for a room, and the nearest standard-size unit, from the room area and a few adjustment factors.
Construction Material Calculator
General material estimate for a project from area or volume and a coverage rate.
Construction Waste Calculator
Waste volume and disposal (dumpster size) for a demolition or build.
All 97 calculators in the BuildFactor library are live. Every one lists its formula, a worked example, its assumptions and its sources on its page.