Free Online Electrical Calculator – Fast & Accurate

If you’ve ever been on-site, in a workshop, or even at your desk and wished you had a quick way to check electrical formulas without flipping through charts or doing manual math — our Electrical Calculator is made for you.

This free, online tool brings together all the essential electrical calculations in one simple interface, so you can focus on your work instead of the numbers.


Whether you’re a professional electrician, an engineer, a student, or just working on a DIY project, electrical calculations are part of the job. Using our calculator means you can:

  • Save time
  • Avoid costly mistakes
  • Quickly get accurate results
  • Work confidently, anywhere, from any device

Our multi-function electrical calculator includes the most requested tools in the industry:

1. Ohm’s Law

Enter any two values (Voltage, Current, Resistance, Power) and instantly get the rest — no manual formulas needed.

2. Power Calculations

Supports both single-phase and three-phase systems, letting you calculate power (W/kW) or determine the required current for a given load.

3. Voltage Drop

Quickly check voltage drop for copper or aluminum cables, single or three-phase, to ensure compliance with standards.

4. Power Factor Correction

Calculate the required kVAr to improve your power factor, saving on energy costs and improving efficiency.

5. Energy & Cost

Estimate daily energy consumption (kWh) and cost based on your load and electricity rate.

6. Motor Full-Load Current

Find the full-load and starting current for single or three-phase motors, based on HP, efficiency, and power factor.

7. Transformer Sizing

Get the kVA rating on both primary and secondary sides for quick sizing and load checks.


  • Electricians – Fast checks during installations or troubleshooting
  • Engineers – Quick reference during design
  • Students – Learn by doing, with real-time results
  • DIYers – Stay safe and accurate in home projects

The calculator works on desktop, tablet, or mobile, so you can use it:

  • On the construction site
  • In the workshop
  • In the classroom
  • At home

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