About the Electrical Unit Converter
Electronics parts are labelled with prefixes: a 4.7 kΩ resistor, a 470 µF capacitor, a 250 mV signal, a 2,000 mAh battery. This page converts six electrical quantities between those prefixes and a few related units. Choose voltage, current, charge, capacitance, resistance or inductance, type a value, pick the units and read the answer, with the same value in every other unit of that quantity listed below. The charge list also includes amp-hours, milliamp-hours and the elementary charge, so you can turn coulombs into Ah or count electrons. This tool only changes units. It does not turn charge into energy, because that needs a voltage; use the mAh to Wh Calculator for that. Results keep twelve significant digits and are shown to eight.
Updated September 2026
How to use the Electrical Unit Converter
- 1Choose the quantity in What are you converting?, such as voltage or capacitance.
- 2Type your number in Value. Decimals and commas are fine.
- 3Pick the unit you have in From and the unit you want in To. The swap button reverses them.
- 4Read the big answer, or look down the list to see the same value in every unit of that quantity.
- 5Press Copy result to take the plain number without thousands commas.
Working with prefixes
Each prefix is a power of ten. Milli is a thousandth, micro a millionth, nano a billionth and pico a trillionth. Kilo is a thousand, mega a million and giga a billion. Converting between two prefixes means moving the decimal point by the difference in steps, which is easy to get wrong by one place when you work quickly.
The converter does the multiplication and then tidies the result to twelve significant digits, so typical conversions come out as clean numbers instead of long tails of decimals.
Charge, current and battery capacity
Charge is what a battery stores and a capacitor holds. The coulomb is the standard unit. A current of one ampere moves one coulomb every second, which links battery ratings in amp-hours to coulombs.
- 1 mAh = 3.6 C
- 1 Ah = 3,600 C
- 1 C is about 6.24 × 10¹⁸ electrons
- To compare energy, multiply Ah by the voltage to get watt-hours
Choosing the right units on a project
Resistors are sold in ohms, kilohms and megohms, capacitors in picofarads to microfarads, and inductors in microhenries to millihenries. Datasheets and calculators do not always agree on the prefix, so a quick conversion avoids a part that is wrong by a factor of a thousand.
For power and energy, see the Power Converter and Energy Converter. For current, voltage and resistance together, the Ohm's Law Calculator solves the missing value.
Features
- Six quantities: voltage, current, charge, capacitance, resistance and inductance
- Prefixes from pico to giga where they are used in practice
- Amp-hour, milliamp-hour, coulomb and electron charge in one list
- All units of the chosen quantity shown together
- Swap button and sensible default units for each quantity
- Twelve significant digits before rounding, so 470 µF is exactly 470,000 nF
- Clear messages for empty, invalid or huge input
- Runs in your browser with nothing sent anywhere
Frequently asked questions
How many volts are in a kilovolt?
A kilovolt is 1,000 volts, a megavolt is 1,000,000 volts and a gigavolt is 1,000,000,000 volts. Going the other way, one volt is 1,000 millivolts or 1,000,000 microvolts. Pick Voltage, then choose the two units to see the exact figure.
How do I convert amp-hours to coulombs?
Multiply by 3,600, because an ampere is one coulomb per second and an hour has 3,600 seconds. So 1 Ah is 3,600 C and 1 mAh is 3.6 C. Divide by 3,600 to go from coulombs to amp-hours.
How many electrons make up one coulomb?
One coulomb is about 6.2415 × 10¹⁸ elementary charges. The charge of a single electron is 1.602176634 × 10⁻¹⁹ coulombs, a value fixed exactly by the modern SI definition. Choose Charge and Elementary charge to see the count.
Can I turn amp-hours into watt-hours with this tool?
No. Amp-hours measure charge, and watt-hours measure energy, which also depends on the battery voltage. Multiply amp-hours by the voltage to get watt-hours, or open the mAh to Wh Calculator, which does this and adds a loss allowance.
What is the difference between nF, µF and pF?
They are a thousand times apart: 1 µF is 1,000 nF and 1 nF is 1,000 pF. A capacitor marked 104 is 100 nF, which is 0.1 µF. Convert here if a datasheet uses a different prefix from the part you hold.
Why does the list show µ and Ω symbols?
Micro is written with the Greek letter µ and ohm with Ω, the official symbols. On a keyboard people often write uF and kohm instead, which are the same thing. The unit names beside the symbols make the match easy to read.
Is a megaohm the same as a milliohm?
No. Megohm, written MΩ, is one million ohms while milliohm, written mΩ, is one thousandth of an ohm. They differ by a factor of a billion, so check the capital or small letter before you read a resistor or a meter.