Editorial approach
Calculator methods, assumptions, source links, limitations, tests and review dates are published so readers can judge an estimate in context. See the Efficienco methodology for the site-wide standard.
Calculators maintained
Home Addition Cost CalculatorReviewed September 2, 2026Bitumen CalculatorReviewed September 11, 2026Building Material CalculatorReviewed September 11, 2026Concrete Block CalculatorReviewed September 2, 2026Linear Feet CalculatorReviewed September 10, 2026HVAC Duct CalculatorReviewed September 2, 2026Recessed Lighting CalculatorReviewed September 11, 2026
Guides written
How to Estimate Building Materials in 2026: Step-by-Step GuideUpdated September 11, 2026Recessed Lighting Layout Guide 2026: Spacing, Lumens & Can LightsUpdated September 11, 2026Build Up vs. Build Out: Home Addition Costs in 2026Updated September 10, 2026CMU Block Sizes and Dimensions: 2026 GuideUpdated September 10, 2026Cost Per Linear Foot Guide 2026: Formula & ExamplesUpdated September 10, 2026How Much Mortar and Core Fill Do I Need? 2026 GuideUpdated September 10, 2026How to Calculate Duct Area in 2026: Round and RectangularUpdated September 10, 2026How to Calculate Linear Feet in 2026: Fence & BaseboardsUpdated September 10, 2026HVAC Trunk, Plenum and Return Duct Sizing: 2026 GuideUpdated September 10, 2026Room Addition Cost in 2026: Prices by Room TypeUpdated September 10, 2026How Many Concrete Blocks Do I Need? Wall Formula and ExamplesUpdated August 30, 2026How Much Does a Home Addition Cost in 2026? Prices by Size and TypeUpdated August 30, 2026How to Size HVAC Ducts: CFM, Velocity, and Friction RateUpdated August 30, 2026
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