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Solar Panel Calculator: How Many Solar Panels Do I Need?

The average U.S. home needs 20 to 30 solar panels to offset 100% of its electricity bill. However, results vary depending on factors like household energy usage and geographic location.

To get started, answer the following questions to calculate how many solar panels you need to power your house.

Solar Panel Calculator

On average, how many KiloWatt-Hours (kWh) do you use per month? (Refer to your electric bill)

Solar Panel Calculator

Recommended System Size


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For more information about how much your solar panel system might cost, keep reading.

Estimate Your Solar Panel System Costs

Now that you have an idea of how many solar panels you need, you can calculate the cost of the solar power system.

Sample electric bill

Step 1: Determine average and daily monthly electricity usage

You probably consume more electricity during certain months of the year. Refer to your utility bills for the past 12 months, and calculate your average usage (kWh) over that period.

You can also estimate your average daily kWh usage by dividing your monthly usage by 30 (the average number of days in a month).

Sample electric bill

Step 2: Calculate the cost of solar panels

One standard solar panel produces about 1.24 kWh per day, and costs around 65 to 75 cents per watt. Solar panels from well-known manufacturers run as high as one to two dollars (or more) per watt.

Based on your results from the solar panel calculator above, you can multiply your recommended wattage by 65 or 75 cents (or more) to get a ballpark cost for all of your solar panels.

Sample electric bill

Step 3: Factor installation costs

Thanks to federal tax credits and increasing demand, solar installation costs continue to drop, making it more affordable to go green. Installation costs fell over 70% in the last ten years, according to the Solar Energy Industries Association.

Based on solar system size, expect to pay around $10,000 or more for solar panels and parts. Then add solar panel installer costs, which range from $5,000 to $10,000 depending on who you hire. In the end, the total cost of purchasing and installing a solar panel system may run you between $10,000 to $20,000 or more.

Read more: What is the true cost of solar panels?

Pro-Tip: Consider Saving Money With DIY Solar

GoGreenSolar House

The next step is to evaluate the different options of solar kits and energy systems.

If you’re looking for the most cost-effective solution, DIY solar kits are the way to go. You can save up to $10,000 (or more) by forgoing professional installation and setting up the solar array yourself!

Installing your own solar panel system is easy when you have a team of experts helping you every step of the way.

GoGreenSolar is the leading retailer in do-it-yourself solar systems, offering step-by-step installation support and a permit approval guarantee to help you save thousands of dollars. Our kits include all the components you need to assemble your solar array.

Learn more:

How to calculate solar payback period

Does solar increase home value?

Explore Our Top DIY Solar Panel Kits

Our 50+ solar panel kits come with installation support, permit approval guarantees and flexible financing options for a hassle-free experience. Browse all our solar panel kits here.

String Inverter

String Inverter

Micro Inverter

Micro Inverter

PV Optimizer

PV Optimizer

Cost $ $$ $$$
Starting Price From $5,183.50+ From $4,645+ From $7,486.49+
kW Range 3kW - 40kW+ 2kW - 40kW+ 4kW - 40kW+
Battery Expansion Expandable, but only if planned for Easily expandable Expandable, but only if planned for
Shading Not ideal for homes with shade Ideal for homes with shade Ideal for homes with shade
Remote Monitoring checked checked checked
Monitoring Options All Systems Only Panel Level and All System Panel Level and All System
Mounting Type Ground Mount Roof Mount Roof Mount
Learn more: 3kW vs. 8kW vs. 20kW of Solar: What Will It Power?

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