53 Converting Between Metric Prefixes

EXAMPLE 1

Express 2500 Volts in Kilovolts

EXAMPLE 2

Express 0.057 Milliamps in Microamps

EXAMPLE 3

Express 5 600 Milliohms in Kiloohms

Conversions

An amp is the measure of the amount of current or electrical energy that is passing through an electric line, whereas a Watt is the unit for measuring electrical power. It is calculated by multiplying the voltage (V) and the current (amps) being used.

Here’s the formula for calculating amps to watts:

Wattage = Amps × Voltage

For example, if you have a 120V device with a 20 Amp label, that’s equivalent to a wattage of 2400. In equation form, that is: 20A × 120V = 2400W

Formula for Converting Watts Into Kilowatts:

P(kW) = P(W) / 1,000
(1 kilowatt = 1000 watts)

For example, if you wanted to convert your 1500W dishwasher to kilowatts, you would do the following calculation:

P(kW) = 1,500W / 1,000 = 1.5kW

Formula to Convert Kilowatts to Megawatts:

P(MW) = P(kW) / 1,000

The power in Megawatts is equal to the power in Kilowatts divided by 1000.

This formula also means that if you would like to convert watts to megawatts, you have to add three more zeros to your equation. The power in megawatts P(MW) can be found by dividing the power in watts P(W) by 1,000,000.

Here’s the Formula to Convert Watts to Megawatts:

P(MW) = P(W) / 1,000,000

For example, if you convert a 100-watt light bulb to megawatts, you will do the following calculation:

P(MW) = 100W / 1,000,000 = 0.000100MW

Kilowatt = a measure of 1,000 Watts of electrical power

Kilowatt-Hour = electrical energy equivalent to a power consumption of 1,000 Watts for 1 hour

Formula for Calculating Watts Into Kilowatt-Hours:

kWh = (watts × hrs) ÷ 1,000

For example, to find the kWh of 1,200 watts for 3 hours:

kWh = (1,200 × 3) ÷ 1,000
kWh = 3,600 ÷ 1,000
kWh = 3.6

Here’s the Formula for Calculating Kilowatt-Hours Into Watts:

watts = (kWh × 1000) ÷ hrs

For example: let’s find the watts of power for 3.6 kWh of energy used in 3 hours.

watts = (3.6 kWh × 1,000) ÷ 3 hrs
watts = 3,600 ÷ 3 hrs
watts = 1200 W