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Off-Grid Calculator

Size Your System for Off-Grid

  1. Enter your zip code
  2. Choose your mounting option
  3. Describe your shade coverage
  4. Fill out the Load Evaluation Calculator
  5. Calculate your system size

Step 1: Enter your zip code

Enter your zip code, and we'll look up the the sun hours in your area.
Sun Hours/Day

How many Sun Hours do you average per day?

This is based on an annual average. Depending on your location and energy usage patterns, you might need a larger system to avoid using a backup generator excessively during the winter months.

You can also look at the Solar Map to find this number.

Typically 4-6 hours, most of the US receives an average of around 5 sun hours per day.
*An overestimation of sun hours will result in an incorrect system calculation.

Step 2: Choose your mounting option

Where do you plan on mounting your solar panels?

Step 3: Describe your shade coverage

How much shade will affect your solar panels?

Step 4: Fill Out Load Evaluation Calculator

Wholesale Solar Load Evaluation Calculator

Watts (V x A)
Hours On per Day
Watt Hours per Day
Show Appliance Consumption Table *
* Use these estimates to provide a
general watt value for your appliances.
Total Watt Hours per Day:
Watt Hours Required Assuming Inherent Efficiency Loss:
Killowatt Hours Per Month:

Step 5: Calculate System Size

Click the "Calculate My System Size button" and we'll calculate your system size.



System Size


Solar Panel Wattage

Approximate Number of

Solar Panels Needed:
Solar Panels

This is a very general system size estimation. Other factors such as shade, location, available panel space, and seasonal use need to be taken into account.

For the most accurate and personalized system size calculation, call our solar experts at 1-800-472-1142.

We want to help you get the system that’s right for you.

Todd, The Off-Grid Guru

Questions? Chat with us!

Todd built his own 3 kW solar system to power his Northern California home, where he lives off the grid with his wife and children. Todd and the rest of the Wholesale Solar team are here to answer any questions you have about designing a system that will fit your needs. Give us a call—we’re here to help.

image of getting started with solar guide
Download Our Solar Battery Guide
A poorly designed system can ruin your batteries. Our Solar Battery Guide will help you size your battery bank properly and keep things running smoothly.