It's essential you know your electricity meter is operating correctly, because if the meter is over reading, you can end up paying more for your electricity than you have actually used. Conversely, if the meter is under reading you may have less expensive electricity bills for a while, but eventually it will be realized and you could end up with a large back payment due.
If you suspect your electricity meter isn't accurate the easiest method is to contact your supplier. Advise them of your concerns and ask that someone is sent to your home to test the meter. Your electricity supplier will be perfectly willing to do so, because it is also in their interests to ensure you pay for the correct electricity usage.
You can easily do a quick accuracy check yourself. Turn off all your appliances, then read the meter and make a note of the reading. Choose an appliance that uses a lot of electricity, such as an electric heater. Read the label to ascertain the wattage. Turn on the appliance for an hour then turn it off. Read the meter again. Deduct the first reading from the second and compare it to the wattage of the appliance you turned on for one hour. The difference between the two readings should equal the wattage on the label of your appliance if the meter is working accurately. Expect the answer to vary by plus or minus 5 percent.
Read the electricity meter. Set the multimeter to read amperes. Place the prongs on the end of the wires from the multimeter onto the output wires from the electricity meter. The prong on the end of the red wire goes to the red wire from the electricity meter, and the prong on the end of the black wire from the multimeter goes to black wire from the electricity meter. Read the multimeter and make a note. Don't turn on or off any electrical equipment for an hour. Read the meter then deduct the first reading from the second reading. Multiply the ampere reading you noted from the multimeter 110; this relates to your home electricity voltage. The answer will equal the figure you worked out from the electricity meter readings if your meter is accurate. Expect up to a 5 percent difference.
If you can't, or prefer not to, contact your electricity supplier, or if you are not happy to undertake a self-test, then arrange for an independent meter tester to check the accuracy of your electricity meter. You will be charged, but if your meter is inaccurate, you may ultimately save money.