Ohm’s Law & Basic Electrical
Tools for voltage, current, resistance, watts, amps, volt-amps, and basic circuit math.
About these electrical calculators
These electrical calculators are designed for fast estimating, planning, and educational use. They can help with common electrical calculations such as voltage, current, resistance, power, watts, amps, wire sizing, voltage drop, conduit fill, breaker sizing, panel loads, motor amps, transformer sizing, generator sizing, solar panel planning, battery capacity, and energy costs.
Common uses
Use these tools to estimate circuit loads, choose wire sizes, calculate voltage drop, compare appliance energy usage, estimate breaker and panel capacity, plan lighting loads, size motors or generators, and work through basic electrical formulas before starting a project.
Important electrical safety note
Electrical work can involve shock hazards, fire risk, conductor ratings, breaker requirements, grounding rules, equipment limits, local codes, and permit requirements. Use these calculators as planning estimates and verify important electrical decisions with a qualified electrician or electrical professional before installing or modifying electrical systems.