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What Size Solar Generator Do I Need? (Simple Calculator + Power Guide)

Buying a solar generator can feel confusing fast.

500Wh… 1000Wh… 2000Wh…

How much power do you actually need?

Too small and it dies quickly.
Too big and you overspend.

This simple guide will help you choose the right size solar generator based on what you actually want to run during a power outage.

Quick Answer (Most People)

If you just want the fast answer:

  • Phones + lights → 300–500Wh

  • Apartment essentials → 500–1000Wh

  • Refrigerator → 1000Wh+

  • Whole home backup → 1500–2000Wh+

For most families, 1000–1500Wh is the sweet spot.

If you already know your situation, you can jump straight to our detailed guides for apartments, refrigerators, or home backup power.

Step 1: List What You Want to Power

Write down your must-have devices:

Common examples:

  • Refrigerator

  • Wi-Fi router

  • Phone chargers

  • Laptop

  • Lights

  • TV

  • CPAP machine

  • Fans

Your generator only needs to cover the essentials.

Step 2: Add Up the Watts

Each device uses a certain number of watts.

Typical usage:

  • Phone charger → 10W

  • Laptop → 60W

  • Router/modem → 10–20W

  • LED light → 10W

  • TV → 100W

  • Refrigerator → 100–200W (600–1200W startup surge)

Example:

Router (20W)
Laptop (60W)
Lights (20W)
Mini fridge (120W)

Total = 220W running

Step 3: Multiply by Hours Needed

Now decide how long you want power.

Formula:

Watts × Hours = Watt-hours (Wh)

Example:

220W × 8 hours = 1760Wh needed

So you’d want a 1500–2000Wh generator.

Quick Size Guide (Easy Chart)

Use CaseRecommended sizeTypical Devices
Phones & Lights300-500 WhPhones, LED Lights, Tablets, Small USB Devices
Apartment Essentials500-1000 WhWi-Fi Router, Laptop, Lights, TV, Fans
Refrigerator Backup1000-1500 WhFull Size Refrigerator, Lights, Router
Extended Outages1500-2000+ WhFridge, Freezer, Multiple Devices, Fans

Real-World Examples

Small Apartment Setup

  • Lights

  • Wi-Fi

  • Phones

  • Laptop

👉 500–700Wh is plenty

See our full guide to the best solar generators for apartments to compare the quietest and most compact options

Refrigerator Backup

  • Fridge

  • Lights

  • Router

👉 1000Wh minimum

We break this down in detail in our guide to the best solar generators for refrigerators, including runtime examples.

Family Emergency Setup

  • Fridge

  • Freezer

  • Lights

  • Devices

  • Fans

👉 1500–2000Wh+

For larger outages, see our picks for the best solar generators for home backup power.

Bigger Isn’t Always Better

Large generators:

  • heavier

  • more expensive

  • harder to store

If you only need phones and lights, don’t buy a 60-lb power station.

Match size to your actual needs.

Pro Tips to Extend Runtime

You can stretch battery life by:

  • Keeping fridge closed

  • Using LED lights

  • Turning off unused devices

  • Charging during the day with solar panels

  • Running appliances only when needed

Small habits can double runtime.

FAQs

Is 500Wh enough?

Good for phones, lights, laptops — not refrigerators.

Is 1000Wh enough for a fridge?

Usually yes, for 8–12 hours depending on efficiency.

Should I oversize?

A little, yes. Double, no.

Not sure where to start? Our best solar generators under $1000 guide is a good place for budget-friendly options.

Final Recommendation

Most people are happiest with a 1000–1500Wh solar generator.

It’s big enough to handle real emergencies without being huge or expensive.

If you’re unsure, start there and you’ll have reliable backup power for nearly any outage.

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