A residential electric meter measures how much energy you use. Energy use is calculated in kilowatt-hours or the number of kilowatts of power used times how many hours of use in a one-month billing period.
The equation for energy is:
Energy = Power x Time
It's often abbreviated like this: E = P x T
The units of the equation are:
kilowatt-hours(Energy) = kilowatts(Power) x hours(Time)
or kWh = kW x hr
By reading the meter at the same time each day, you will get an idea of the amount of electricity you used. By writing each daily reading in an "Energy Diary," you can "chart" increases and decreases in energy use. By making notes when a particular energy activity is done like doing the laundry or cooking, you will know how your "energy dollar" is being spent.
Notice that some of the dial hands on the meter above turn "clockwise" and some turn "counter-clockwise." Look at the first dial, it is turning "clockwise," and the hand is between the 7 and the 8. Record the number that the hand just passed - (in this case it is 7). The second dial is turning "counter-clockwise" and is just past the 3, so that is the next number to write down and so on.
Look at the dial to the right of the dial being "read." If the hand on the right has moved past "zero," write down the number the hand on the left is pointing to - (using the same dials, it would be the 7).
If the hand on the right is not past "zero," then write down the next lowest number on the dial being read. In picture above, the meter reads "73256."
Now, if you read this meter at the same time tomorrow, subtract today's reading from tomorrow's reading to determine the number of kilowatt-hours used in one day.
To calculate the cost of the energy you used, multiply the number of kilowatt-hours by the cost per kilowatt-hour charged by your electric utility. Take a look at your electric bill and see if you can find your "cost per kilowatt-hour." For example, if your utility company charges 9 cents per kilowatt-hour, multiply by $.09.