OutageReadyBackup power, worked out

See what your power station or generator can run in a power outage.

Free calculators and guides for US homes. Pick your appliances, like the fridge, sump pump, CPAP or furnace, and find out how long a battery lasts, what size generator you need, and how many solar panels it takes to recharge.

Calculate battery runtimeSize a generator

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How to use OutageReady

Whether you are shopping for a power station or generator, or already own one and want to know what it can handle, three steps get you a clear answer.

  1. List what has to keep running

    Think about what matters most in an outage: the fridge, a sump pump, a CPAP, the furnace, lights and Wi-Fi. Our wattage chart shows what each one draws.

  2. Check your power source

    Enter those appliances in the runtime calculator to see how long a battery lasts, or the generator calculator to find the size you need.

  3. Read the guide for each appliance

    Each appliance guide covers startup surge, real-world runtime, safe hookup and tips to stretch your power further.

Calculators

Enter your own numbers or start from typical values.

Power station runtime calculatorHow many hours your battery lasts with the appliances you pick. Generator size calculatorRunning and starting watts, with the size class to shop for. Solar charging calculatorPanel watts and days to recharge, based on your sun hours. Appliance wattage chartRunning and starting watts for 23 household appliances.

Can a power station run it?

Runtime tables, startup surge and practical tips for each appliance.

See all guides
Can a power station run a refrigerator?Runtime by battery size, startup surge, and how long food stays safe.Can a power station run a sump pump?Startup surge, runtime in a storm, and when a dedicated backup pump is the better choice.Can a power station run a CPAP machine?Nights per charge with and without the humidifier, and why DC power lasts longer.Can a power station run a window air conditioner?Why AC drains batteries fast, what size works, and cheaper ways to stay cool.Can a power station run a space heater?Why electric heat drains batteries in minutes, and what to use instead.Can a power station run a chest freezer?One of the easiest loads for a battery, with runtimes of a day or more.Can a power station run a microwave?Why a 1,000 W microwave needs a 1,500 W power station, and how many minutes of cooking you get.Can a power station run a gas furnace?Blower wattage, runtime in cold weather, and the safe way to connect a hardwired furnace.Can a power station run a well pump?Why 240 V is the first hurdle, how big the startup surge is, and how much water a battery buys you.What size generator do you need to run a house?Running and starting watts for essentials, comfort and whole-home backup.How many solar panels to charge a power station?Calculator for panel watts and charging days, by battery size and sun hours.

Learn the basics

Plain-English explainers for choosing and using backup power.

Watts vs. watt-hours: what's the difference?What the two numbers on every power station mean, and the one formula that connects them.LiFePO4 vs. lithium-ion (NMC): which power station battery is better?Cycle life, weight, safety and cold weather: how the two battery types compare for backup power.Pure sine wave vs. modified sine wave: which do you need?Why the shape of the power matters for CPAPs, fridges and electronics, and how to check what you have.Inverter generator vs. conventional generator: which is better for an outage?Noise, clean power, fuel use and price: how to choose between the two types of portable generator.Winter storm power outage: how to stay warm and safeStaying warm safely, protecting pipes and food, and what to power first when a winter storm cuts the electricity.

Why you can trust these numbers

The math is on the page

Every calculator shows its assumptions, and you can replace our typical values with the numbers on your own appliances.

No paid rankings

Ads and affiliate links keep the site free. They never decide what we calculate or recommend.

Safety over shortcuts

We explain how things work and send you to a licensed electrician for anything wired into your home.

Every guide is checked against the formulas in how we calculate. Read more about OutageReady.