Portable power station run-time calculator

Updated

Add what you want to run and for how many hours a day. We work out how long each power station lasts on its tested capacity, not the number on the box, and we count the power the station uses on itself.

Independent testers measured 75% to 96% of the rated capacity on the 36 models here. On top of that, a station switched on uses 9 W to 74 W on itself in the tests we hold. Both are in every answer below.

What do you want to run?

Fridges and freezers

Screens

Fans and air

Anything else

A CPAP, router, laptop or phone? Add your own device and use the watts on its label or power adapter. How to find a device's watts

Your list is empty. Tap a device above, or try a full-size fridge for a day.

Charging from solar optional

Add your panels to see how much longer a station lasts with the sun topping it up.

Time of year

Add up the ratings: two 100 W panels make 200 W. Sun figures from NLR's PVWatts, for panels in the open, facing south and tilted 20 degrees. How we count solar

Power stations that can do it

How long will a portable power station run a refrigerator?

A full-size fridge with a freezer uses about 57 W on average: the median of 2,397 ENERGY STAR certified models is 498 kWh a year. On the 27 models we track with at least 1,800 W of continuous output, that gives about 10.4 hours on the OUPES Mega 1 up to 41.0 hours (1.7 days) on the Jackery HomePower 3600 Plus.

1,800 W is the lowest continuous rating among the stations that ran a full-size fridge in CNET's fridge test, so smaller stations are left out of that range. For measured run times, see our fridge guide.

How does the calculator work?

  • Energy for a day (watt-hours) is each device's watts times its hours a day, times how many you have, added up. It is what the battery has to hold.
  • Most power at once (watts) is everything on your list switched on together. The station's output rating has to cover it, or it switches off.
  • Start-up burst only counts if you enter start-up watts for a device with a motor, such as a pump or a fridge. It is the most power at once plus that device's extra kick as it starts.
  • Run time is the station's tested usable capacity divided by your devices' average draw over a day plus the station's own use. It assumes the station stays switched on the whole time.
  • Which power stations can do it: the tested capacity covers the days you set, counting the station's own use, with 20% to spare; its output covers the most power at once; and its surge rating covers any start-up burst.

For example, the Anker SOLIX C2000 Gen 2 has 1,812 Wh of tested usable capacity and uses about 12 W itself. With a 57 W fridge: 1,812 ÷ (57 + 12) = about 26.3 hours.

The station's own use

We hold a figure for 9 of the 36 models here: idle draws measured by testers, and our sums from CNET's fridge test (sources below). Across all the figures we hold, it runs from 9 W to 74 W. For a model without one, we use 21 W, the middle of those figures, and say so next to the answer.

Usable capacity comes from tests at 100 W or more, so it already includes the station's losses at that load. Adding its own use on top errs on the short side for big loads, and matters most for small ones. Why stations run out early on small loads

The sums assume your devices plug into the AC outlets. Running them from the USB or 12 V ports can use less: Hobotech measured the EcoFlow DELTA Pro 3 using about 49 W idling with its AC outlets on, and about 13 W with only its DC outputs on.

Where do the device figures come from?

Each preset is the median of the ENERGY STAR certified models sold in the US, from ENERGY STAR's product data (read Oct 19, 2026). For fridges and freezers it is the yearly kWh on the EnergyGuide label, turned into average watts (kWh × 1,000 ÷ 8,760 hours).

Device Watts Basis Models
Refrigerator with freezer (full-size) 57 W average 498 kWh a year, 18.7 cu ft 2,397
Compact refrigerator (mini fridge) 28 W average 246 kWh a year, 3.3 cu ft 1,712
Upright freezer (full-size) 50 W average 438 kWh a year, 14.7 cu ft 474
Compact freezer 28 W average 249 kWh a year, 4.3 cu ft 134
TV, 32-inch 31 W Measured power 9
TV, 43-inch 64 W Measured power 11
TV, 55-inch 96 W Measured power 21
TV, 65-inch 118 W Measured power 22
Computer monitor, 24-inch 13 W Measured power 479
Computer monitor, 27-inch 17 W Measured power 519
Ceiling fan, high speed 31 W Measured power, 52 in blade span 662
Air purifier, highest speed 25 W Measured power, 250 sq ft room 244

Three things to know about these figures:

  • They are certified models. ENERGY STAR models use less than the federal limit, so an older or uncertified fridge, TV or fan can use more. Some sizes rest on few models.
  • They are averages, not start-up watts. A fridge or freezer needs a burst of extra power for a moment when its compressor starts. ENERGY STAR doesn't publish that, so add it from the manual if you know it, under "Use your own figures" on that device.
  • Hours a day are yours to set. Fridges and freezers start at 24 hours, because they stay plugged in; everything else starts at 1 hour.

How do I find my own device's watts?

  • The label or nameplate gives watts, or amps and volts: multiply those for watts. That is the most it draws, so it overstates the average.
  • A power adapter (laptop, router, CPAP) lists its output in volts and amps. Multiply them for the most it can supply.
  • The yellow EnergyGuide label on a fridge or freezer gives kWh a year. Enter it under "Use your own figures" on that device and the calculator turns it into average watts.
  • A plug-in watt meter shows what a device really draws. On a fridge, leave it for a full day to get the average.

CPAP and other medical devices: check the machine's own power figures in its manual and ask your supplier. A heated humidifier or heated tube uses much more than the machine alone. Have a backup plan.

Is this a solar generator calculator?

Yes. A solar generator is a portable power station sold with solar panels. Add your panels under "Charging from solar" and the calculator counts what they put back each day.

How do you count solar charging?

  • Sun: the PVWatts model (version 8) from NLR, the National Laboratory of the Rockies (formerly NREL), for 9 cities, one in each part of the country. It gives the energy a panel delivers each day for each watt of its rating, after heat and PVWatts' standard 14.08% for dirt, shade, wiring and the like. We use the yearly average, or the worst month. The set-up: standard modules, fixed open rack, tilted 20 degrees, facing south.
  • Your own sun hours: if you enter a sun-hours figure (kWh/m² a day, from PVWatts or a solar map), we scale it by 80%, the middle of what PVWatts keeps across our cities.
  • The station's limit: each station takes only so much solar input (its maker's figure, on each review page). Panels above that don't count. We have no figure for the Duracell G800, so solar is left out for it.
  • Losses in the station: energy from the panels is stored and then given back, so we take the same share the station delivered in tests.
  • A day with no sun: to count as able to do it, a station must still carry one full day of your list on its own, with 20% to spare: a cloudy day, or a power cut that starts at night.

Check that your panels' voltage suits the station's solar input range (on each review page) before you buy. Panels laid flat, facing another way or partly shaded give less than these figures.

Sources

No published surge rating: BLUETTI Elite 30 V2, Duracell G800, DJI Power 1000 V2, BLUETTI Elite 200 V2 and BLUETTI Apex 300. These pass the surge check only when their continuous rating covers it.