Calcjaw’s BlogProfessional calculator suite built for trade professionals. Construction, HVAC, electrical, and plumbing calculations — fast, accurate, and mobile-first.https://calcjaw.notchip.comResidential Electrical Load Calculation: NEC Article 220 Guidehttps://calcjaw.notchip.com/residential-electrical-load-calculation-nec-220https://calcjaw.notchip.com/residential-electrical-load-calculation-nec-220How to calculate the electrical service load for a residential panel — the NEC Article 220 standard method and optional method. Required for service sizing and permit applications.Sat, 16 May 2026 00:00:00 GMTManual J Heat Load Calculation: HVAC Sizing Guide for Technicianshttps://calcjaw.notchip.com/manual-j-heat-load-calculation-guidehttps://calcjaw.notchip.com/manual-j-heat-load-calculation-guideHow to calculate heating and cooling loads using Manual J — the ACCA standard method. Covers the inputs, the math, and why rule-of-thumb sizing fails.Fri, 15 May 2026 00:00:00 GMTConduit Fill Calculations: NEC Chapter 9 Guide for Electricianshttps://calcjaw.notchip.com/conduit-fill-calculator-guidehttps://calcjaw.notchip.com/conduit-fill-calculator-guideHow to calculate conduit fill correctly using NEC Chapter 9 tables — maximum fill percentages, wire area lookup, and common mistakes that fail inspection.Thu, 14 May 2026 00:00:00 GMTPipe Sizing for Plumbers: Water Supply, Drainage, and Gas Pipinghttps://calcjaw.notchip.com/pipe-sizing-plumbing-guidehttps://calcjaw.notchip.com/pipe-sizing-plumbing-guideHow to size water supply pipes, drain/waste/vent systems, and gas piping correctly — with the UPC and IRC references behind each calculation.Fri, 01 May 2026 00:00:00 GMTHow to Calculate Concrete for Footings, Slabs, and Columnshttps://calcjaw.notchip.com/concrete-calculator-guidehttps://calcjaw.notchip.com/concrete-calculator-guideStep-by-step concrete volume calculations for common pours — footings, slabs, walls, and columns. Includes waste factor guidance and ordering tips.Thu, 30 Apr 2026 00:00:00 GMTDuct Sizing for HVAC: The ASHRAE Equal Friction Method Explainedhttps://calcjaw.notchip.com/duct-sizing-hvac-guidehttps://calcjaw.notchip.com/duct-sizing-hvac-guideHow to size supply and return ducts correctly using the equal friction method — the ASHRAE standard approach used by HVAC professionals.Thu, 30 Apr 2026 00:00:00 GMTWire Sizing and Voltage Drop: What Every Electrician Needs to Knowhttps://calcjaw.notchip.com/wire-sizing-voltage-drop-guidehttps://calcjaw.notchip.com/wire-sizing-voltage-drop-guideA practical guide to NEC-compliant wire sizing and voltage drop calculations for residential and commercial work — with the exact formulas used in Calcjaw.Thu, 30 Apr 2026 00:00:00 GMT