Free online electrical calculators and sizing references for engineers, electricians, and students. Each tool comes with the formula, a worked example, and the relevant standard, so you can check the result rather than just trust it. Start with the groups below, or browse every tool underneath.
Motor current (three-phase): I = P ÷ (√3 × V × power factor × efficiency), with P in watts and V as line voltage. Voltage drop: keep it low, because it matters most on long runs and low-voltage systems like 12V and 24V lighting or solar. The NEC informational notes suggest about 3% on a branch circuit and 5% overall, and other standards set their own limits. Always verify: calculators give an estimate, so confirm results against your local code and the manufacturer’s data before installing. For the code behind the numbers, see our Electrical Standards guides.
Use our Transformer Inrush Current Calculator to estimate magnetizing inrush current precisely. Designed for power system engineers, this tool helps analyze transformer startup behavior, ensuring accurate protection and reliable system performance
A Single Phase Transformer Calculator is an essential tool for electrical…
Transformers are essential components in power systems, ensuring efficient voltage conversion…
Easily estimate your electric vehicle charging expenses with our EV Charger Energy Usage Cost Calculator. Find out how much it costs to charge at home or on the go, compare 7kW charger costs, and understand your EV energy consumption in real time. Perfect for EV owners who want accurate, money-saving insights
Electric vehicles (EVs) are revolutionizing transportation, offering a cleaner, more efficient,…
Balancing loads in a three-phase electrical system is one of the…
When planning an electrical upgrade or new installation, one of the…
Discover the Electrical Work Estimate Calculator, the best tool for quick and accurate electrical load estimation. Simplify your project planning, calculate costs, and get precise results for home and commercial electrical work.
Power Factor Correction Capacitor Calculator to determine the required capacitor kVAR, improve power factor, reduce reactive power, and optimize electrical system efficiency with practical formulas and examples.
Electrical Load estimation for residential projects is one of the most…
Free motor overload setting calculator — enter motor kW/HP and voltage to get FLA, recommended relay setting, and min/max range instantly.
Accurately calculate the right earth cable size for your electrical or solar installation. Use our Earth Cable Size Calculator to find safe, efficient earthing conductor sizes based on current, length, and voltage drop. Ideal for engineers, electricians, and homeowners.
Choosing the right breaker size for AC is more than just…
Easily calculate the right circuit breaker size with our free Circuit Breaker Size Calculator. Ensure electrical safety, prevent overloads, and select the correct breaker for your wiring and load requirements.
Understanding electrical power measurements is essential for engineers, electricians, and even…
When dealing with electrical systems, understanding the relationship between power and…
EV Charger Cable Size Calculator: Best Tool helps you determine the correct cable size for Level 1 and Level 2 EV chargers based on current, distance, and voltage drop. Ensure safe, NEC-compliant EV charger installation with accurate wire size calculations.
Electric motors are at the heart of countless industrial and commercial…
Short circuit calculations are critical for transformer protection. When a fault…
What is Short Circuit Current and Why Is It Important? Short…
Understanding Subpanel Wire Size and Its Importance A subpanel is a…
Choosing the correct wire size is one of the most important…
Choosing the correct wire size is critical in both residential and…
Choosing the correct wire gauge is essential for safe and efficient…
Free cable size calculator for single and three-phase circuits. Covers IEC 60364, BS 7671 and NEC sizing with derating and voltage drop checks.
A current in parallel calculator uses Ohm’s Law and Kirchhoff’s Current Law (KCL) to determine how current divides among parallel resistors. The formula follows:
Understanding the Voltage Drop on Resistor Calculator A Voltage Drop on…
A load computation calculator is a essential tool for accurately determining the total electrical load required for residential, commercial, and industrial setups.
Use our Electrical Service Size Calculator to accurately calculate electrical load demand, panel capacity, and service entrance size for residential and commercial installations. Fast, reliable, and easy-to-use online tool.
Whether you’re designing a new house, upgrading your electrical systems, or considering a backup power source, an electricity load calculator in kW for home can be an invaluable tool.
