An electric power meter is a very accurate instrument that measures the amount of electricity you use. If you look through the glass enclosure, you will see a rotating metal disc. It rotates in proportion to the amount of electricity that's being used at that time. The more electricity you are using at any given moment, the quicker the disc rotates. Each revolution represents a specific amount of electricity. The disc causes gears to rotate, which in turn make pointers on a dial move, showing the amount of electricity used [source: Georgia Power]. Electricity is measured in kilowatt hours. One kilowatt hour of electricity can supply enough energy to keep ten 100 watt bulbs burning for one hour. The electric company representative reads your meter at regular intervals, and you're then billed accordingly. If the meter reader couldn't gain access to your meter, you will receive an estimated bill [source: Nevada Energy].

Your power meter is made up of five dials:

- The first dial on the right measures units and rotates clockwise.
- The next dial to the left measures tens and rotates counter-clockwise.
- The dial third to the left measures hundreds and rotates clockwise.
- The fourth dial to the left measures thousands and rotates counter-clockwise.
- The last dial on the left measures ten thousands and rotates clockwise.

Read your power meter from right to left and write down the numbers that the each arrow points to.

- If the arrow on a dial is in between two numbers, record the lower number. For example if the pointer is between the three and four, record three. The exception is if the pointer is if the pointer is between zero and nine, in which case you record nine. Zero is always the beginning of the next revolution, and nine is considered the previous number. Thus nine is lower than zero.
- If the arrow on the dial is exactly on a number, record that number [source: Nova Scotia Power].