About

WattCalcs is a hub of technical calculators for electrical and off-grid power work — wire sizing, voltage drop, ampacity, conduit fill, Ohm's law, breaker size, solar arrays, battery banks, inverters, generators, RV/van 12V power and energy cost — in US English, for DIYers, electricians and off-grid builders in the United States.

The author, Francesco Zinghinì, is Author and curator · builder of deterministic online calculators (open-source Python projects). He is NOT a licensed electrician, Professional Engineer (PE) or master electrician. His competence for a calculator hub is building deterministic online calculators (engineering training, open-source Python projects): a transparent method, correct formulas, cited constants (AWG geometry and resistance, NEC ampacity, resistivity, NREL sun hours) and verifiable examples.

The formulas are timeless electrical engineering (Ohm's law, voltage drop, energy = power × time, conductor geometry) verified numerically against known examples (see the self-check). The reference constants are stable engineering data, cited per tool and in /sources/. NEC tables are revised on a roughly three-year cycle: each NEC-derived value states the edition it references and you should verify it against the edition adopted by your AHJ. The results are estimates for planning and education, NOT a substitute for a licensed electrician's design or local code compliance. The cost tools contain no tariffs — you enter the rate yourself.