When building a home or performing renovations to an existing property, interior and exterior doors are a common feature that may be replaced or upgraded. Before you make these changes to your home, enlist the help of a local specialist to understand the size of the door you're looking to install or replace, as well as the size of the rough opening where the door will be installed.

Today, both interior and exterior doors come in one of several standard door sizes. But because there are a number of different door sizes, as well as different types of door thickness to choose from, it's important to choose doors carefully and make sure your measurements are right before you purchase, prep and install one of these doors.

Here's an overview of the standard door width, height and thickness you'll find in many homes, including how to match the right door to the right rough opening.

Standard Door Dimensions: How Tall is a Door?

Standard door height is a fairly easy metric to understand. The average interior and exterior door is 80 inches or six feet, eight inches tall.

While some doors may be taller than this—especially when the door is placed on the exterior of a home—these oversized door sizes may need to be custom-made. Additionally, you may find some interior doors, particularly in older homes, where the door height is lower than eighty inches. This is most likely to be found in basements or upper floors where a low ceiling makes it impossible to fit a standard door.

In cases where your desired door is slightly taller or shorter than 80 inches, you have two options to find the right fit. The first is purchasing an oversized door that fits this non-standard rough opening. Alternatively, slightly smaller door openings can be accommodated by an expert by cutting down the size of a standard 80-inch door. One common instance where you might need to trim the door's height is in a room where carpet has been added, reducing the overall dimensions of the rough opening.

How Wide is a Door in a Typical Home?

When it comes to average door width, you can expect a lot more variance in the size of your doors. Typically, the standard exterior door is 36 inches wide, while the standard interior door size is 32 inches wide. But these common door widths are far from the rule.

While you're likely to see less variance in the width of an exterior door—unless your home features double-doors that combine two smaller doors to make a larger opening—some interior doors may feature smaller widths. While 32 inches is typically the minimum width required for a door that serves as a passage from one room to the next, other types of doors found in your home—such as doors for utility access and closets—may feature doors that range from 24 to 30 inches wide.

Additionally, homes built to Americans with Disabilities Act (ADA) specifications will need all doorways to feature oversized, 36-inch doorways. Before you go door shopping, you should always measure the width of these doors to make sure you understand the width you're looking for.

Comparing Standard Door Size to Rough Opening Size

How wide is a door compared to the door's opening? What about the height of the opening vs. the height of the door? If you try to purchase and install a door that perfectly matches the dimensions of the door opening itself, you're going to find yourself in a world of trouble.

When looking to replace interior and exterior doors, it's important to know the difference between the size of the door itself and the rough opening for the door and its frame. If you're looking to replace a door while keeping the existing frame, the measurements of the door itself—and the opening inside the frame—is all you need to consider, although bear in mind that adding a new door to an old frame can lead to issues regarding fit and is not recommended.

If you're replacing the door and frame, you need a rough opening that can accommodate both. Typically, the required rough opening for a given door and its frame can be calculated by adding one inch to the width of the frame, and .5 inch to its height. If you measure your current rough opening and it isn't large enough to accommodate this size, you may need to expand the rough-in opening to properly fit a standard door and frame.

What About Door Thickness?

Height and width aren't the only metrics to consider when replacing or installing doors. You also need to choose the right thickness for your door. For interior doors, the standard thickness is 1 3/8 inches, although some doors may be thicker than this. Exterior doors tend to have added thickness to improve security and insulation: you're likely to find exterior doors with a thickness of 1 3/4 inches.

As you shop for doors, pay attention to their thickness and the benefits and drawbacks of a thinner vs. thicker door. Thickness adds soundproofing in interior doors, but it can also be heavier and harder to open and close. If you're choosing doors to fit to an existing frame, you will want to match the new door's thickness to the old one to make sure it properly fits in the frame.

If you're looking to replace an exterior door at your home, trust North Georgia Replacement Windows to professionally replace your current door with a high-quality fiberglass or steel door. Contact us today to request a proposal!