How long would your backup power last?
Flip on the circuits you can't lose. We check output, start-up surge and 240 V, then play the outage hour by hour for a power station, a home battery and your EV.
Free · no sign-up · specs checked October 28, 2026
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Your breaker panel
4 circuits onRefrigerator
700 W run · 2.9 kW start
Qty1700 W covers the compressor and defrost peaks; real use is about 1 kWh a day for an ENERGY STAR model.
Chest freezer
700 W run · 2.9 kW start
Microwave
1.0 kW run
Coffee maker
1.0 kW run
Hot plate / one burner
1.3 kW run
Dishwasher
1.2 kW run · 2.4 kW start
Your result
- Running at once
- 790 W
- Starting peak
- 3.0 kW
- Energy per day
- 1.7 kWh
- Voltage
- 120 V
Jackery HomePower 2000 Plus v2
Lasts the full 24 h
with 5% left when the grid comes back.
EcoFlow DELTA 3 Plus + 1 × DELTA Pro 3 Smart Extra Battery (one at a time)
Covers your list · 5.1 kWh · 1.8 kW out · 3.6 kW surge
24 h+$719 + batteriesJackery HomePower 2000 Plus v2
Covers your list · 2.0 kWh · 2.4 kW out · 4.8 kW surge
24 h+$1,069Jackery HomePower 3600 Plus
Covers your list · 3.6 kWh · 3.6 kW out · 7.2 kW surge
24 h+$1,709BLUETTI Apex 300
Covers your list · 2.8 kWh · 3.8 kW out · surge not published
24 h+$1,599Anker SOLIX F3800 Plus
Covers your list · 3.8 kWh · 6.0 kW out · surge not published
24 h+$2,399.99EcoFlow DELTA Pro 3
Covers your list · 4.1 kWh · 4.0 kW out · 8.0 kW surge
24 h+$2,799Jackery HomePower 3600 Pro Max
Covers your list · 3.6 kWh · 4.0 kW out · 8.0 kW surge
24 h+$1,799Jackery Explorer 5000 Plus
Covers your list · 5.0 kWh · 7.2 kW out · 14 kW surge
24 h+$3,149Anker SOLIX F2000
Can't start your biggest motor · 2.0 kWh · 2.4 kW out · surge not published
BLUETTI AC180
Can't start your biggest motor · 1.2 kWh · 1.8 kW out · surge not published
—$499Jackery Explorer 1000 v2
Runs it, but not for the whole outage · 1.1 kWh · 1.5 kW out · 3.0 kW surge
13 h$499Anker SOLIX C1000 Gen 2
Runs it, but not for the whole outage · 1.0 kWh · 2.0 kW out · 3.0 kW surge
13 h$499.99
How the planner decides
A backup fails in one of three ways, and the planner checks all three before it shows a runtime. First, continuous output: everything you switched on can run at the same time, so the unit has to deliver the sum of their running watts. Second, starting power: the largest motor on your list (sump pump, well pump, furnace blower, compressor) needs a short kick of two to three times its running watts. Third, voltage: well pumps, central AC, dryers and electric water heaters run on 240 V, which most portable stations don't provide without a second unit or the maker's home panel.
Only then does energy come in. The planner drains the battery at your average draw plus inverter losses, quarter-hour by quarter-hour, starting at the hour you set for the outage, and adds solar during daylight. That is why an outage that starts at 6 p.m. and one that starts at 9 a.m. can end differently with the same panels.
Make it match your house
- Open a circuit and type the watts printed on your appliance's label: the start-up surge scales with it.
- Hours are hours of actual running. A sump pump in a storm might run 10 minutes an hour, which is about 4 hours a day.
- For central AC, the deciding number is the LRA (locked-rotor amps) on the outdoor unit's label. Compare it to the battery's rating: a Powerwall 3 is rated for 185 LRA.
Every appliance links to the source of its numbers, and every product spec carries its check date on the power station page. The full method is on our about page.
Questions people ask
How do I calculate how much backup power I need?
Add the running watts of everything that may be on at once (that's the continuous output you need), add the biggest single motor's start-up kick on top (that's the surge), then multiply each appliance's watts by its hours of use to get watt-hours per day. Divide the battery's capacity by your average draw, after about 10–12% inverter losses, for the runtime.
Why does my fridge show 700 W but only about 1 kWh a day?
Because a compressor cycles. 700 W is the conservative running figure generator makers use to size for start-up and defrost; the actual energy an ENERGY STAR refrigerator uses is about 1 kWh per day. The planner uses the first number to check output and the second to compute runtime.
What does 'can't start your biggest motor' mean?
Pumps, compressors and blowers draw two to three times their running power for a fraction of a second when they start. If a unit's surge rating is below that peak, it shuts off or refuses to start the motor even with a full battery. When a maker doesn't publish a surge rating, we only count its continuous output.
Do you include solar?
Yes, if you add panels. Solar follows a sine curve from 6 a.m. to 6 p.m. at 75% of the panels' rating, the equivalent of about 5.7 hours at the panels’ full rating on a clear day, and is capped by each unit's solar input. Storm days produce less, so treat solar as a bonus.
Can I connect a power station to my house wiring?
Only through a transfer switch, an interlock kit or the maker's home panel, installed by a licensed electrician. Never plug a power station or car into a wall outlet to feed the house: it can electrocute utility workers and neighbors.