Twelve calculators covering the maths electricians reach for most — from Ohm's Law to solar array sizing.
The core relationships behind every circuit.
Find voltage from current and resistance.
Find power from voltage and current.
Estimate energy consumed over time.
Find current from power, voltage, and power factor.
Sizing cables, breakers, and materials before you start.
Estimate demand load and current draw.
Get a recommended minimum cable size.
Estimate voltage drop across a cable run.
Get a recommended breaker rating.
Roughly estimate cable length needed.
Generators, inverters, and solar.
Estimate the generator size needed.
Estimate inverter size and battery capacity.
Estimate solar array size and panel count.