Your meter shows a running total in kilowatt-hours (kWh), not a rate. To find out what you used over a period, read it twice and subtract the first reading from the second. Digital and smart meters show the number directly: read it left to right and ignore anything after a decimal point. Dial meters need a trick: read the dials right to left, take the lower number whenever a pointer sits between two, and remember that adjacent dials turn in opposite directions.
That second reading is where the value is. Once you can take a reading, you can run an elimination test that finds exactly what is drawing power in your house while you are not using anything, which turns out to be a surprising amount.
The four meter types at a glance
Look at the face before anything else. Almost every US home has one of four types, and each is read slightly differently.
| Meter type | What you see | How to read it | Data you can get |
|---|---|---|---|
| Dial (electromechanical) | Four or five small clock-like dials and a spinning disk | Right to left, lower number rule | Manual readings only |
| Digital (non-communicating) | LCD number, no visible disk | Left to right, whole numbers | Manual readings only |
| Smart (AMI) | LCD, often with a utility logo and signal icon | Left to right; may cycle screens | Hourly or finer data via utility portal |
| Net (solar or bidirectional) | Usually a smart meter with extra screens | Separate delivered and received totals | Import and export registers |
Smart meters are now the norm. According to the US Energy Information Administration, about 73% of residential electric meters were advanced metering infrastructure (AMI) by 2022. The EIA defines AMI as meters that record use at least hourly and send that data to the utility and the customer at least once a day, so if you have one, your utility’s app or web portal will usually show far more detail than manual readings ever could.
How do you read a digital or smart meter?
An LCD display shows a number, typically five to eight digits, sometimes cycling through several screens. Read left to right including leading zeros, and ignore anything after a decimal point. The kWh total is the one labeled “kWh” or shown with a register code; your utility’s meter guide lists which code means total consumption.
Some meters cycle between displays: a display test (all segments lit), total consumption, current demand, and on solar-equipped homes, energy exported. If yours cycles, note which screen you read so the next reading is comparable. This is the most common source of confusing results.
On a net meter, the two figures that matter are energy delivered from the grid to the house and energy received from the house back to the grid. Your net use for the period is the change in delivered minus the change in received.
How do you read a dial meter?
Four or five small dials, each with a pointer. The rules, as utilities such as National Grid explain them in their customer guides:
- Read right to left.
- Adjacent dials rotate in opposite directions — the first clockwise, the next counterclockwise, alternating. Look at the numbering on each face to see which way it runs.
- When a pointer sits between two numbers, take the lower one. Between 9 and 0, the reading is 9.
- When a pointer looks exactly on a number, check the dial to its right. If that one has passed zero, use the number. If it has not yet reached zero, use one lower.
That last rule is where nearly all misreadings happen. Write the digits down in the order you read them, then reverse them so the left-hand dial ends up first. Some meters also print a multiplier (such as “x10”) on the face; if yours does, multiply the result by it.
How do you calculate how much electricity you used?
Subtract the earlier reading from the later one. The result is kilowatt-hours consumed over that period. Divide by the number of days for a daily average, which makes periods of different lengths comparable.
For context, the EIA reports that the average US residential customer used about 865 kWh a month in 2024, at an average price of 16.5 cents per kWh. Your own figure will vary widely with climate, home size and whether you heat with electricity.
| What you want | Calculation | Example |
|---|---|---|
| Use over a period | Later reading − earlier reading | 45,210 − 44,350 = 860 kWh |
| Daily average | kWh ÷ days | 860 ÷ 30 = 28.7 kWh/day |
| Approximate cost | kWh × your price per kWh | 860 × $0.165 = $141.90 |
| Instant draw (dial meter) | 3.6 × Kh × revolutions ÷ seconds | 3.6 × 7.2 × 1 ÷ 20 = 1.3 kW |
| Baseline draw | kWh overnight ÷ hours | 1.2 kWh ÷ 8 h = 0.15 kW |
| Annual cost of baseline | kW × 8,760 × price | 0.15 × 8,760 × $0.165 = $217 |
The instant-draw formula comes from University of Arkansas extension guidance on reading electric meters. The Kh value (the watt-hours per disk revolution) is printed on the meter face, and you time one full turn of the black mark on the disk with a stopwatch. It lets you see what switching on a single appliance does to your draw in real time.
What is using electricity when everything is off?
Idle load, sometimes called standby or phantom power, is electricity drawn by devices that are switched off, asleep, or simply always on. It is larger than most people expect. A Natural Resources Defense Council study that combined smart meter data from about 70,000 northern California homes with in-home audits found idle load made up nearly 23% of household electricity use, costing an estimated $165 a year for the average US household. It is invisible on a bill and easy to find with the meter.
- Take a reading late at night.
- Turn off everything you can and leave the house running as it normally would overnight.
- Take another reading in the morning, and note the hours elapsed.
- Subtract, divide by hours. That is your baseline draw in kW.
Multiply by 8,760 (the hours in a year) to get an annual figure. A baseline of 0.15 kW is around 1,300 kWh a year before anyone has switched anything on.
Some of that baseline is unavoidable. The fridge, freezer, furnace controls and smoke alarms should stay on. The rest is the target. To find the culprits, repeat the test with one circuit switched off at the breaker, or work through suspects with a plug-in energy monitor. The usual offenders are set-top boxes and DVRs, game consoles in instant-on mode, older desktop PCs and printers, always-on chargers and power bricks, secondary fridges and freezers, and towel rails or other heated devices left on a timer nobody set.
A smart meter makes this easier still: look at the hourly data for 2 a.m. to 5 a.m. on any ordinary night. The lowest hour is your baseline, with no need to stay up taking readings.
The holiday check
Easier than the overnight test if you have old bills: find a billing period when you were away. If usage over that period sits at 40–50 percent of a normal period, a substantial fraction of your electricity is being consumed by things that run regardless of whether anyone is home.
Why don’t my bill and my reading match?
Common and usually harmless. Utilities frequently issue estimated bills between actual reads, and the bill will say so somewhere, often with an “E” beside the reading. Submitting your own reading corrects it. Meters also roll over from 99999 back to zero, and the billing period rarely matches the calendar month you assumed.
Other things to check before assuming a fault:
- You read a different screen. Demand or exported energy instead of total consumption, on a meter that cycles.
- A multiplier applies. Larger homes and some older meters show a fraction of the real figure.
- The bill covers more days. A 34-day period will look high next to a 28-day one; compare daily averages instead.
- Rates changed. The same kWh can cost more after a seasonal or tiered rate change.
If the discrepancy is large and persistent after a genuine read, ask the utility for a meter test. Faults do occur, though they are rarer than billing estimates, and many utilities and state regulators set rules for how a disputed meter is tested.
Turning readings into something useful
A single reading tells you nothing. A weekly reading, written on a note stuck inside a cupboard, tells you a great deal within a month — whether a change you made worked, when your consumption climbs, and what a cold snap actually costs.
Two things worth measuring this way, because both are large and both are free to adjust: your water heater’s set temperature, which runs continuously in the background, and heating and cooling behavior, where using ceiling fans properly lets you move the thermostat several degrees without anyone noticing.