Building & Carpentry calculators

Framing, envelope, and site calculators for builders and carpenters.

• Hip and Valley Rafter Length CalculatorHip or valley rafter length = common run × √(2 + (rise ÷ 12)²), for two equal-pitch roof planes meeting at a right angle.
• Rafter Length and Birdsmouth Cut CalculatorCommon rafter length = run × √(1 + (rise ÷ 12)²), and a birdsmouth notch may not exceed one-fourth of the rafter depth under the IRC.
• Retaining Wall Block and Gravel CalculatorBlocks needed = courses × (wall length ÷ block length), where courses = exposed height ÷ block height plus the buried base courses, with waste added.
• Roof Snow Load Calculator (ASCE 7-16)Flat roof snow load pf = 0.7 × Ce × Ct × Is × pg, and a sloped roof load is that value times the slope factor Cs.
• Wall R-Value Calculator (Layers and Framing)A wall's effective R-value is lower than its insulation R-value because studs carry heat around the cavity; the parallel path method combines both paths.