Electrical Unit Converter: Current, Voltage, Charge and Power
Which electrical unit converter do you need?
Pick the quantity you are measuring: amperes for current, volts for voltage, coulombs or amp-hours for charge, VAR for reactive power, VA for apparent power and VARh for reactive energy.
Each quantity below has its own converter and its own prefix ladder. They are grouped here because an electrical measurement is rarely read on its own.
Where Most Readers Start
- convert apparent power between VA and kVA
- convert a charge between coulombs and amp-hours
- convert a voltage between volts and kilovolts
Every Converter in This Family
One row per converter, with the quantity it measures and the SI unit that quantity is held in. Three of them share a dimension and none of the three converts into another.
| Quantity | SI unit | Converter |
|---|---|---|
| apparent power | volt-ampere | Apparent power units |
| electric charge | coulomb | Charge units |
| electric current | ampere | Current units |
| reactive energy | volt-ampere-hour reactive | Reactive energy units |
| reactive power | volt-ampere reactive | Reactive power units |
| voltage | volt | Voltage units |
How This Family Is Organised
The figures below are the knowledge base's own, and they cover this sub-hub rather than the whole family.
Current, voltage, charge, reactive power, apparent power and reactive energy are separate quantities with separate units, and each one scales by the same SI prefixes.
An SI prefix multiplies a unit by a power of ten: k is 10^3, M is 10^6, G is 10^9, m is 10^-3, micro is 10^-6 and n is 10^-9. The prefix belongs to the unit, so 1 kV is 1000 V.
- Electrical Unit Converter hub, tool link count 6
Which Electrical Quantity Are You Measuring?
Current, voltage and charge are separate quantities and are read with separate instruments. Real, apparent and reactive power all come out as a voltage multiplied by a current, so they carry the same dimension and different unit names, and a figure is meaningless until the name is attached to it.
Frequently Asked Questions
What is the difference between watts, volt-amperes and VAR?
Watts measure real power, volt-amperes measure apparent power and VAR measure reactive power. All three share a dimension, so the unit names are what say which component of the supply a figure describes.
What is power factor?
The ratio of real power to apparent power. It says how much of a supply rated in volt-amperes turns into watts, and working it out is a calculation rather than a unit conversion.
Why do three electrical quantities share the same dimension?
Each of them is a voltage multiplied by a current, so the dimension comes out the same. What differs is the part of the alternating cycle each one measures, which is why they carry separate unit names.