Solar Panel Dimensions: How Big Are Solar Panels and How Many Do I Need?

Don’t underestimate the power of sunshine. You can save around $1,380 per year on energy bills by installing solar panels. You just need to choose the right size and quantity for your system. This guide provides a rundown on solar panel dimensions and how to estimate how many you need.

What Are the Standard Solar Panel Dimensions?

Solar panels are made up of tiny squares called cells that convert sunlight into electricity. The more cells, the higher the wattage. Most homes use 60-cell panels that are roughly 65-by-39 inches. Depending on the brand you buy, you’ll find a couple of inches of variation on either dimension. 

For 60-cell panels, the cells are arranged in a 6-by-10-cell grid. Most homes use anywhere from 15 to 34 solar panels, each emitting 250 to 350 watts of electricity per hour in ideal conditions. The output does depend on the efficiency of the solar panel.

Solar Panel Dimensions by Type

Though 60-cell panels are the standard for residential properties, other options may work better in certain scenarios. For example, you can choose a smaller, portable panel for an RV or as an emergency backup. A larger solar panel can help reduce the chance of energy loss in areas with lower light. 

If you’re unsure how to proceed, a solar panel installer can help you design the right solar panel system for your home. Here are some average solar panel dimensions based on the type of panel.

40-Cell

40-cell panels are smaller than the standard solar panel, producing an average of 200 to 240 watts of electricity per hour. These portable systems are primarily used for camping, fishing, and RVs or as backups during power outages. The average portable system measures 60-by-24 inches with a depth of around 1 inch. 

60-Cell

60-cell solar panel dimensions are around 65-by-39 inches. Depths range anywhere from a fraction of an inch to 1 1/2 inches. Most residential installations use this size solar panel, which produces an average of 250 to 350 watts of electricity.

72-Cell

72-cell solar panels measure about 80-by-40 inches with a depth of 1 1/2 inches. This option is popular for homeowners requiring a larger output or wanting to improve efficiency and for homes without space constraints. They produce an average of 350 to 400 watts of electricity.

96-Cell

96-cell solar panel dimensions are around 62-by-41 inches with a depth of around 1 3/5 inch. These solar panels consist of a 7-by-12-cell grid. They’re growing in use because they help reduce power loss by increasing voltage. These panels have an output of 450 to 500 watts.

Half-Cut Solar Panels

Half-cut solar panels fit twice the number of solar cells in the same amount of space as a standard solar panel. You’ll find 120- or 144-cell panels with similar dimensions to standard 60- and 72-cell panels. These tend to be the most efficient option, so you’ll need fewer panels in your system.

Factors That Influence Solar System Size

A number of factors influence not only the dimensions of each individual solar panel but also the size of your entire solar power system. It’s a delicate balance of efficiency, sunlight, and your home’s energy requirements. 

Energy Requirements 

According to a 2022 report from the U.S. Energy Information Administration (EIA), the average home uses 899 kilowatt-hours (kWh) per month (or around 30 kWh per day). You’ll need to make sure your system can handle your daily energy needs. For higher-than-average energy use, you can install a larger system. 

Direct Sunlight

Solar panels don’t need direct sunlight to work, but shade does impact their efficiency. You’ll see a lower output in areas obstructed by shade (whether it's from a tree or nearby building) and almost no output at night. For this reason, most people install solar panels on their roofs where they can soak up the most sun possible.

If you have a particularly shady yard, you might need larger panels or more panels to achieve the energy you need. 

Geographic Location

The more sunlight, the fewer panels you’ll need. This can vary dramatically from location to location—and we’re not just talking about the direct exposure in your yard. Areas closer to the equator experience more sunlight than those further from the equator, and it changes seasonally.

For example, Arizona is one of the sunniest states with an average of 10 hours of sunlight on the shortest day of the year. Meanwhile, the darkest areas of Alaska don’t get any sunlight during a large portion of the winter. 

Monocrystalline vs. Polycrystalline

The composition of your solar panel doesn’t impact the dimensions of the panel, but it will impact the overall weight of the system and how many panels you’ll need. All solar panels are made from silicon crystals, but the composition varies between types.

You can choose monocrystalline or polycrystalline solar panels. Monocrystalline solar cells are made from a single silicon crystal. They’re more efficient and perform better in low-light situations. Polycrystalline panels are made from multiple crystals. They’re more affordable, but you’ll need more of them to power your home.

Energy Efficiency

The energy efficiency of each panel impacts the overall size of your system. Larger panels can be more efficient because they capture more sunlight, but certain half-cut models fit more solar cells in a compact space. The higher the energy efficiency, the fewer panels you’ll need.

Cost

You’ll need to consider your budget before choosing a solar panel. The standard 60-cell panel is often the most budget-friendly, but you might need larger solar panels in certain circumstances. Larger panels have a higher energy output because they capture more light, but they cost more up front because they’re heavier and difficult to install.

Keep in mind that many states have government programs that help offset the cost of solar panel installation. 

How to Calculate the Size and Number of Solar Panels

There are several considerations when choosing both the size of your solar panels and how many solar panels to use in your system. It’s not a simple DIY—even if you get the numbers right. You’ll still need to install the panels correctly, which requires electrical work and climbing on your roof. At best, you could potentially void your solar panel warranty. At worst, you could injure yourself or others. 

Instead, hire a solar panel installer near you with the expertise to plan and complete the job effectively. If you want to estimate the size of your system before your contractor starts the job, follow these steps:

1. Look at your electric bill: Check out your monthly energy bill to find the number of kWh you use. You can spring for a home energy audit to see if there’s anywhere you could improve.

2. Calculate daily energy usage: Once you have your monthly usage, divide that number by 30 to estimate your daily energy usage. 

3. Find the daily amount of sunshine: Next, calculate the number of peak hours of sunshine you get per day. You can use this chart from the National Renewable Energy Laboratory (NREL) to help estimate, but it depends on where you live and the season. 

4. Determine the energy production required: Divide your daily energy usage by the number of hours of sunlight per day. For example, if you use 30 kWh per day and have 5 hours of sunlight, you’ll need enough panels to produce 6 kW per hour.

5. Estimate solar panel output: To find the right number of panels, you’ll need to know the number of kilowatts each panel can produce in ideal conditions. Most residential panels produce between 250 to 400 watts. You can convert this number to kilowatts by dividing it by 1,000. For example, a 350-watt solar panel would produce 0.35 kW.

6. Calculate the number of panels required for your system: Divide the energy production required (the number you got in step four) by the solar panel output (the figure from the previous step). This is the total number of panels you’ll need in your system. For example, if you need 6 kW per hour of sunlight and your panels produce 0.35 kW, then you’ll need 17.14 panels. You can round up to 18 panels or purchase larger wattage panels with a higher output to make up the difference. 

This figure is just an estimate, and there are other factors that impact the amount of energy required. A pro will factor in the climate, shade that could obstruct the panels, and how sunshine and your energy requirements can change from season to season. They’ll be able to tell which type of system and which panel size and number of panels will suit your home best.