A plug-in watt meter sits between an appliance and the wall outlet and shows how much power the appliance draws. Most also add up the energy used over time. The main choices are the load limit, the voltage range, the readouts and how easy the screen is to read.
The six meters below are all plug-in units, from the long-running Kill A Watt to a wide-voltage model listed at 3680 watts. Limits, readouts and sizes come from each listing page and are the makers’ own claims. We have not used these meters ourselves. Where a listing disagrees with itself, we say so.
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What to Look For
| Feature | Why it matters |
|---|---|
| Load limit | The meter has a maximum in watts or amps |
| Voltage range | Make sure it matches your outlet |
| Readouts | Watts, volts, amps, kWh, frequency and power factor vary |
| Display | A backlight helps behind furniture |
Specs at a Glance
| Meter | Display modes | Load limit | Notes |
|---|---|---|---|
| MECHEER PM01-US | 7 modes | Not clearly listed | Backlight with 5 time options; UL listed |
| MECHEER 8 modes | 8 modes | 1800 W overload default | ABS body; 5.5 x 3.5 x 2.5 in |
| HBN U167J | 9 modes | 15 A; 1875 W | Backlight turns off after 15 s; ETL |
| P3 Kill A Watt P4400 | Four settings | 15 A; 115 V | Needs 1 CR123A battery; 6.4 oz |
| KETOTEK KTEM02-US | 5 button interface | 15 A; 1800 W | ABS; 6.7 oz; FCC; alarms |
| SURAIELEC WMA02A | Several readouts | 16 A; 3680 W | 90 to 250 V; 90 day data hold; 5.9 oz |
The 6 Best Plug-In Watt Meters
1. MECHEER Watt Meter Power Meter Plug, 7 Modes
A plug-in meter that shows power in watts, energy in kWh, volts, amps, hertz, power factor, cost, minimum and maximum power and running time across seven display modes. The screen is 2.36 by 1.85 inches with a 180 degree viewing angle and five backlight time options. The listing says UL and has overload protection, but the voltage fields read 12 volts minimum and 120 volts maximum, which is unclear.
Suits: checking everyday appliances. Strengths: a large screen and many readouts. Weaknesses: the voltage and load limits are unclear. Skip it if you need a clearly stated amp limit.
View Watt Meter Power Meter Plug Home Electricity Usage Monitor 7 Modes Display on Amazon
2. MECHEER Upgraded Watt Meter Power Meter Plug, 8 Display Modes
An eight-mode meter showing watts, kWh, volts, frequency, amps, power factor, unit rate and total cost. The maker says the default overload point is 1800 watts, at which the display flashes a warning. The body is ABS and measures 5.5 by 3.5 by 2.5 inches. The model field says PMP-N-1 while the part number says WM03-US, and the certification field says CE.
Suits: a basic plug-in check. Strengths: a stated 1800 watt overload point. Weaknesses: mixed model numbers. Skip it if you want a UL mark, since this listing names CE.
View Upgraded Watt Meter Power Meter Plug Home Energy Monitor 8 Display Modes on Amazon
3. HBN Watt Meter Plug with Backlight, 9 Display Modes
A plug-in meter with nine data views: watts, apparent power, kWh, usage time, frequency, power factor, volts, amps and cost. The maker lists 15 amps, 125 volts and 1875 watts, a 1 year warranty and an ETL mark. The backlight shuts off after 15 seconds. The details also name a Wi-Fi protocol and touch control, which does not match a one-button meter, so treat those fields with care.
Suits: people who want many readouts. Strengths: nine views and a stated warranty. Weaknesses: odd fields in the details. Skip it if you want the backlight to stay on.
4. P3 P4400 Kill A Watt Electricity Usage Monitor
The original-style Kill A Watt with an LCD that counts consumption in kilowatt-hours. The maker describes four settings, cost over a day, week, month or year, and says it is built for 115 volt, 15 amp use and works with inverters. It weighs 6.4 ounces, measures 8.4 by 2.1 by 6.1 inches and needs one CR123A battery. The certification field reads No.
Suits: a familiar meter with a battery-backed display. Strengths: stated 15 amp and 115 volt limits. Weaknesses: it needs a battery and lists fewer readouts. Skip it if you want a backlight.
View P3 P4400 Kill A Watt Electricity Usage Monitor on Amazon
5. KETOTEK Watt Meter Power Meter Plug KTEM02-US
A five-button meter that shows kWh and cost, watts and VA, true RMS volts and amps, frequency and power factor, and maximum and minimum power. The maker lists 15 amps and 1800 watts, ABS material, 6.7 ounces and an FCC mark. It sets alarms for overload, kWh and cost, and it only counts cost when the appliance draws more than 2 watts.
Suits: people who want alarms. Strengths: true RMS readings and alarm settings. Weaknesses: five buttons take learning. Skip it if you want a one-button meter.
6. SURAIELEC Outlet Watt Meter, 90-250V
A wide-voltage meter that the maker lists at 90 to 250 volts, 0 to 16 amps and 0 to 3680 watts, with an overload warning adjustable from 680 to 3680 watts. It states Class 1.0 accuracy with resolutions of 0.1 watt, 0.1 volt, 0.001 amp and 0.001 kWh, and keeps data for 90 days with a rechargeable battery. The listing text we read does not state the plug type, so check it fits your outlet.
Suits: higher-voltage outlets. Strengths: a wide range and a data hold. Weaknesses: the plug type is not stated. Skip it if you only use standard 120 volt outlets.
View Outlet Watt Meter, 90-250V Wide Range Power Meter Cost Calculator on Amazon
Care and Setup
- Plug the meter into the outlet, then plug the appliance into the meter.
- Check the load limit against the label on your appliance.
- Set the electricity rate if the meter has a cost mode.
- Replace the battery on models that use one.
Mistakes to Avoid
- Plugging in an appliance that draws more than the listed limit.
- Reading the cost figure without setting the rate first.
- Assuming every meter fits every outlet.
- Trusting a listing field that conflicts with the rest of the page.
Watt Meter FAQ
What does a plug-in watt meter measure?
It shows the power an appliance draws, and most models also add up energy in kilowatt-hours. Some add volts, amps, frequency and power factor.
Which meter lists the highest load?
The SURAIELEC lists 3680 watts and 16 amps. The HBN lists 1875 watts, and the KETOTEK and the MECHEER 8 mode list 1800 watts.
The Short Version
For a large screen, the first MECHEER. For a stated overload point, the second MECHEER. For nine readouts, the HBN. For a long-running design, the Kill A Watt. For alarms, the KETOTEK. For wide voltage, the SURAIELEC.