To read your electric meter, record the cumulative energy reading in kWh, then subtract the previous reading and apply any billing multiplier specified by your utility. On a mechanical meter, read the numbered dials; on a digital or smart meter, identify the energy register rather than the instantaneous power display. The difference represents electricity used between those readings—not automatically the usage for your billing period unless the dates, meter, and register match.
Electric Meter Types and the Reading to Record
| Meter or display type | What to record | How to determine energy use | Main condition or pitfall |
|---|---|---|---|
| Mechanical dial meter | Digits from the numbered energy dials, read left to right | Subtract the previous reading; apply the confirmed billing multiplier | Adjacent dials turn in opposite directions; between 9 and 0, record 9. |
| Digital meter | The cumulative kWh register | Subtract the previous reading from the same register | Record leading zeros and identify the unit before copying the number. |
| Smart meter with rotating screens | The screen identified by your utility as cumulative energy in kWh | Compare the same energy register at both readings | Date, time, voltage, instantaneous kW, and display-test screens are not cumulative kWh. |
| Meter with a billing multiplier | The applicable energy reading and utility-confirmed multiplier | ((\text{current}-\text{previous})\times\text{multiplier}) | Do not infer a multiplier from unrelated nameplate numbers or apply it twice. |
| Solar or bidirectional meter | The utility-designated net register or separate import and export registers | Compare matching registers using the utility’s instructions | Grid imports, grid exports, and total household consumption are different quantities. |
The basic calculation is the same for a dial meter and a smart meter: compare cumulative energy readings over a defined period. Smart meters add communication and may display several other measurements, so selecting the correct screen matters as much as copying the digits accurately. Read only an intact meter that you can safely view from an accessible location. Do not remove covers, break seals, pull the meter, or attempt adjustments or repairs. If the meter is damaged or cannot be reached safely, contact the utility rather than trying to access it yourself.
How to Read a Mechanical Dial Electric Meter
A mechanical meter uses a series of numbered dials to represent a cumulative reading. The pointers on neighboring dials rotate in opposite directions, but you still record the resulting digits from left to right. The important distinction is between the number a pointer has passed and the number it is approaching.
- Identify the numbered dials used for the electricity reading.
- Read those dials from left to right.
- When a pointer is between two numbers, record the smaller number.
- When it is between 9 and 0, record 9—not 0.
- When a pointer appears exactly on a number, check the dial immediately to its right. If that right-hand dial has not completed its turn to zero, record the preceding number on the left-hand dial.
- Copy the complete reading, including any leading zeros, and record the date and time.
Dial-Reading Illustration
The following is a hypothetical five-dial example. It describes pointer positions rather than representing a particular meter model.
| Dial position, left to right | Pointer position | Digit to record |
|---|---|---|
| First | Between 2 and 3 | 2 |
| Second | Between 4 and 5 | 4 |
| Third | Between 9 and 0 | 9 |
| Fourth | Between 6 and 7 | 6 |
| Fifth | Between 1 and 2 | 1 |
The resulting reading is 24,961. The third digit remains 9 because that pointer has not yet completed its turn to zero. These reading rules follow National Grid’s Massachusetts instructions. The right-hand check prevents a common error when a pointer looks as though it has reached the next number. For example, if a pointer appears to be on 6 while the next dial to its right is still between 9 and 0, record 5 for the left-hand dial. It is still completing the previous cycle. For a utility-provided visual example, National Grid’s Massachusetts meter-reading page includes an annotated dial illustration showing how its example produces a reading of 3,597. Use the illustration to understand the pointer relationship, not to assume that every meter has the same number of dials.
How to Read a Digital or Smart Electric Meter
A digital display is easier to copy, but it can show the wrong quantity for your purpose. Cumulative kWh measures energy accumulated over time; kW describes the rate of electricity use or generation. A current kW reading cannot replace two cumulative kWh readings when checking period usage.
- Check the meter number against the meter identification on your bill.
- Watch the display cycle and identify the cumulative kWh screen using your utility’s instructions.
- Record the register code or label along with the number.
- Preserve leading zeros and any displayed decimal places in your own record. Follow the utility’s specific formatting instructions when submitting a reading.
- Record the date and time, then repeat the process later using the same register. Do not assume that all digital displays follow the same sequence. PG&E describes different screen arrangements for its Landis+Gyr and GE meters, while National Grid’s Massachusetts guide identifies screen code 404 as cumulative energy use. Those are utility-specific examples—not universal meter codes.
Recognizing the Correct Screen
These hypothetical displays illustrate why the unit and label matter:
ENERGY 024961 kWh
POWER 001.25 kW
TEST 888888
In this illustration, record 024961 from the energy screen. The 1.25 kW value is a power reading, and the all-eights screen is a display test. PG&E documents similar distinctions between cumulative energy, current power, and segment-test displays on its meters.
A screen showing 888888 does not necessarily mean the meter has recorded that much energy. It can be a segment test used to verify the display. Likewise, a decimal number labeled kW is not the cumulative kWh reading needed for a usage calculation. Photographing the correct screen can make later checking easier. Keep the register label, reading, and meter identification visible where possible, especially at a property with several meters.
Calculate Electricity Use Between Two Readings
For matching cumulative energy readings, use:
[ E=(R_{\text{current}}-R_{\text{previous}})\times M ]
where:
- (E) is electricity used during the reading interval, in kWh.
- (R_{\text{current}}) is the later energy-register reading.
- (R_{\text{previous}}) is the earlier reading from the same meter and register.
- (M) is the billing multiplier confirmed by the utility. LG&E and KU publish this subtraction-and-multiplier method for determining actual usage. The multiplier matters when the meter registers only a proportion of the energy passing through the metering installation.
Worked Example: A Single Energy Register
The following numbers are hypothetical, not utility averages or actual customer data.
| Input | Example value | Unit or condition |
|---|---|---|
| Previous reading | 24,961 | kWh |
| Current reading | 25,386 | kWh |
| Confirmed billing multiplier | 1 | Dimensionless |
| Reading interval | 30 | Days |
| Meter and register | Unchanged | Same cumulative import-energy register |
| Other assumptions | No rollover or meter replacement | Required for straightforward subtraction |
Substitute the values:
[ E=(25{,}386-24{,}961)\times1=425\text{ kWh} ]
The property imported 425 kWh during this hypothetical 30-day interval. Average daily energy use is:
[ \frac{425\text{ kWh}}{30\text{ days}} \approx14.17\text{ kWh/day}
]
This daily average helps compare periods of different lengths. It does not identify peak demand or show when the electricity was used. For a unit check:
[ 425\text{ kWh}\times1{,}000=425{,}000\text{ Wh} ]
One kWh equals 1,000 Wh. The site’s kWh converter is the relevant internal resource for checking energy-unit conversions; converting units does not establish which meter register or multiplier applies to your account.
Worked Example: A Meter With a Multiplier
Assume a separate hypothetical installation has:
- Previous register reading: 8,120.
- Current register reading: 8,145.
- Utility-confirmed billing multiplier: 40. Then:
[ E=(8{,}145-8{,}120)\times40 =25\times40
=1{,}000\text{ kWh}
]
The register increased by 25, but the calculated energy use is 1,000 kWh because of the confirmed multiplier. This example explains the calculation; it does not establish a typical multiplier for commercial meters. Use the factor applicable to that specific register and account. A billing multiplier may combine internal meter scaling and external metering-transformer ratios. Do not substitute a transformer ratio for the billing multiplier without utility confirmation, and do not multiply a utility-provided kWh total again if it already includes that scaling.
Electric Meter Reading Record
A useful record identifies what was measured, when it was measured, and how the result was calculated. Keeping only the digits can create ambiguity if the meter cycles through several registers or is replaced between readings. The blank cells below are intended for your own readings.
| Reading date and time | Meter ID | Register label or code | Unit | Reading | Confirmed multiplier | Photo or notes |
|---|
Record at approximately the same time of day when comparing daily or weekly use. For a bill check, however, prioritize the utility’s billing-period boundaries rather than an arbitrary calendar month.
Check the Reading Against Your Electric Bill
A meter reading is cumulative; billed usage is the energy assigned to a particular billing interval. National Grid’s Massachusetts bill explanation identifies total usage as the kWh used between the previous and current meter readings and distinguishes actual readings from estimated readings.
- Confirm that the bill identifies the same meter.
- Check the previous and current reading dates.
- Match the register used on the bill to the register you recorded.
- Subtract the bill’s previous reading from its current reading.
- Apply the confirmed multiplier if the listed readings require it.
- Compare that result with the bill’s kWh usage—not its total amount due.
- Check whether either reading is estimated before treating a difference as an error. A reading taken several days after the utility’s closing date includes a different interval, so it should not be expected to match the closed billing period. Compare equivalent dates and registers before drawing conclusions. Smart meters can still produce estimated bills when communication is interrupted. National Grid’s Massachusetts guidance states that delayed transmission may result in temporary usage estimates, which are updated when actual data becomes available. For a discrepancy, retain the readings, dates, register labels, and photographs, then use your utility’s reading-submission or billing-review process. National Grid’s Massachusetts customers, for example, have an official meter-reading submission process; customers elsewhere should use their own utility’s equivalent service.
Conditions That Change the Calculation
Register Rollover or Meter Replacement
Straight subtraction assumes that the register has not rolled over and the meter has not changed. For a hypothetical five-digit register that resets after 99,999, a move from 99,850 to 000125 represents:
[ E=(100{,}000-99{,}850)+125=275\text{ kWh} ]
That result assumes one rollover and a multiplier of 1. Confirm the register’s actual rollover value before using this method. A replacement meter is a different situation. Do not subtract the old meter’s reading from the new meter’s reading. Obtain the old meter’s closing reading and the new meter’s opening reading, calculate each segment separately, and apply the appropriate multiplier to each.
Solar Imports and Exports
A bidirectional meter may display net energy or separate delivered and received quantities. PG&E’s California guidance describes both net-energy displays and model-dependent delivered/received indicators. Follow the instructions for your meter rather than interpreting an arrow or label without context. For a meter with separate registers, calculate the change in each register independently. Import minus export gives net grid energy over that interval, but it does not reveal total household consumption because electricity generated and consumed on-site does not pass through the grid meter. Do not treat net kWh as a guaranteed billing calculation. The applicable tariff determines how imports, exports, and credits are handled.
Time-of-Use Energy and Demand
A total kWh reading shows how much energy accumulated, not necessarily how much fell into each rate period. PG&E states that its SmartMeter display does not show peak, partial-peak, and off-peak usage separately; customers can use their online account to view hourly net usage. Likewise, cumulative kWh does not identify billing demand in kW. A usage check verifies an energy quantity, not the complete bill or the applicable demand calculation.
Meter-Reading Self-Check
- The meter can be viewed safely without opening or disturbing equipment.
- The meter identification matches the account being checked.
- Both readings come from the same cumulative energy register.
- The recorded unit is kWh, not kW, volts, or another measurement.
- Dial readings account for alternating directions and the 9-to-0 transition.
- The billing multiplier is confirmed and applied only once.
- The comparison uses matching dates or clearly identifies a different interval.
- Estimated readings, solar registers, rollover, and meter replacement have been considered.
- Any unresolved discrepancy is supported by dated readings and photographs. Manual readings and calculators are useful cross-checks, not meter-accuracy certifications or electrical design approvals. They do not replace the utility’s meter-specific instructions, manufacturer documentation, NEC requirements, local AHJ requirements, or appropriate professional judgment.