Fireplace dimensions range from 15” width x 16” height x 4” depth at the smallest, to 108” width x 77” height x 35” depth at the largest. These measurements are for a fully assembled fireplace.
- Smallest: 15”W x 16”H x 4”D
- Largest: 108”W x 77”H x 35”D
The dimensions for a firebox alone are 6” width x 2” height x 3” depth at the smallest, to 80” width x 45” height x 24” depth at the largest. These dimensions come into play if you are sizing a fireplace insert.
Two detailed charts can be found below of dimensions for gas and electric fireplaces, as well as information on specific fireplace types such as modern fireplace dimensions and wood-burning fireplace dimensions.
Standard Fireplace Dimensions
A standard fireplace has approximately 35” width x 29” height x 14” depth.
Here’s a more specific break-down of typical fireplace dimensions for gas and electric fireplaces:
Standard Gas Fireplace Dimensions
An assembled gas fireplace has a 43” width, 43” height, and 18” depth on average. The standard dimensions for a gas firebox are 36” width x 35” height x 16” depth.
Standard Electric Fireplace Dimensions
A standard electric fireplace has a 55” width x 31” height x 13” depth assembled, while an electric firebox has a 33” width x 20” height x 7” depth.
Dimensions of Gas Fireplace
The following chart provides the average dimensions for a gas fireplace, as well as the minimum and maximum dimensions that a gas fireplace could possibly have.
Dimensions Of Gas Fireplace
| Average | Minimum | Maximum | |
| Assembled Width | 43 inches | 32 inches | 55 inches |
| Assembled Height | 43 inches | 31 inches | 53 inches |
| Assembled Depth | 18 inches | 15 inches | 28 inches |
| Firebox Width | 36 inches | 23 inches | 45 inches |
| Firebox Height | 35 inches | 21 inches | 45 inches |
| Firebox Depth | 16 inches | 13 inches | 24 inches |
Note: This data is based on 305 popular fireplaces on the market.
Dimensions of Electric Fireplace
Below you can find a chart that offers the dimensions for electric fireplaces, including both the average dimensions and the minimum to maximum range for this type of fireplace.
Dimensions Of Electric Fireplace
| Average | Minimum | Maximum | |
| Assembled Width | 55 inches | 15 inches | 108 inches |
| Assembled Height | 31 inches | 16 inches | 77 inches |
| Assembled Depth | 13 inches | 4 inches | 35 inches |
| Firebox Width | 33 inches | 6 inches | 80 inches |
| Firebox Height | 20 inches | 2 inches | 39 inches |
| Firebox Depth | 7 inches | 3 inches | 16 inches |
Fireplace Dimensions by Type
The following section provides the standard dimensions for most common types of fireplaces.
Outdoor Fireplace Dimensions
A typical outdoor fireplace will have:
- Width between 36” – 180” or 3 – 15 feet
- Height between 48” – 180” or 4 – 15 feet
- Depth between 36” – 72” or 3 – 6 feet.
As you can see, outdoor fireplaces tend to be bigger than indoor fireplaces. However, the firebox dimensions for an outdoor fireplace are the same as for an indoor one, so you don’t have to worry too much about finding a firebox that fits!
Corner Fireplace Dimensions
Corner fireplaces have an average width of about 40 inches, although they can range in width from 40 inches to 45 inches or more at the largest. The width for an assembled corner fireplace with a 40-inch opening is usually about 65 – 68 inches. Standard corner fireplace height is around 42 inches, and most corner fireplaces have a depth of at least 24 inches.
Double Sided Fireplace Dimensions
Double sided fireplaces (also known as see-through fireplaces) range from about 36” to 48” wide. The average height is difficult to calculate, because there are so many different styles of double sided fireplace with widely varying heights.
For example, right now it is popular to use a linear double sided fireplace, which has an average height of 18” – 36,” while a more classic double fireplace style has an average height of about 35 inches. Double sided fireplace depth will fall somewhere between 15 and 30 inches.
Wood Burning Fireplace Dimensions
Wood burning fireplaces have an average depth of 16” – 20,” a width of 36” – 48,” and a height of 21” – 42.”
Linear Fireplace Dimensions
Also known as contemporary fireplaces, modern fireplaces, or rectangular fireplaces due to their long rectangular shape, linear fireplaces tend to have a shorter height of 18 to 36 inches. The depth of a linear fireplace is also shorter than average at about 12 inches. The length is where these fireplaces really vary from traditional fireplace dimensions, ranging from as short as 48 inches to longer than 100 inches.
Rumford Fireplace Dimensions
Typical dimensions for a Rumford fireplace are 30” – 50” width at the fireplace opening, 35” – 54” height, and 20” – 28” depth.
Rumford fireplaces are especially common in homes built between 1800 and 1850, so if you have a home from that 50-year period there is a very good possibility that you have this unique kind of fireplace.
ID Tip: The defining feature of a Rumford fireplace’s dimension is a narrow width opening and a very tall height opening.
Dimensions of Fireplace Parts
Below you can find standard dimensions for the main parts of a fireplace, including the mantel, surround, hearth, and insert.
Fireplace Mantel Dimensions
The mantel should be at least 12 inches above the firebox for safety.
Mantel should be at least 3 inches longer on either side than the firebox, for a total of 6 inches longer. This is the minimum, but designers recommend getting a mantel that is 6 inches longer on either side than the firebox, for a total of 12 inches longer. So, if you have a 36” firebox, you would get a 48” mantel. This is a matter of aesthetics, so the details are up to you. Most fireplace mantel shelves are 7-8” deep.
Fireplace Surround Dimensions
As you can imagine, the correct dimensions for a fireplace surround depend primarily on the dimensions of the firebox. One helpful rule of thumb is that the mantel should always be at least as wide as the legs of the surround. So, if the legs are 4” wide, the mantel should be no shorter than 4.” The best surround size for you will mostly depend on your space. If your ceilings are low to average in height (8-9 feet) then you will want a small fireplace surround, while high ceilings may require a larger surround to look balanced.
Fireplace Hearth Dimensions
To be up to code, a fireplace hearth must extend at least 16” beyond the firebox, and have a width that extends 8” to the sides of the firebox on each side. This is the minimum requirement for a fireplace opening that is 6 square feet or less. If your fireplace opening is larger than 6 square feet, the hearth needs to extend 20” beyond the firebox and at least 12” on either side. The bigger your hearth is, the less risk there is of fire spreading outside the fireplace!
Fireplace Insert Dimensions
Fireplace insert widths run from 25” for a small insert to about 36” at the largest. The depth of the insert will be about 13” at the shortest to 19” at the longest. The average height for a fireplace insert ranges from 17” – 24.” Make sure to measure your firebox opening precisely so you can get an insert with a great fit.
FAQs
What is a standard size fireplace opening?
A standard size opening for a gas fireplace is 36” width x 35” height, and for an electric fireplace a standard size opening is 33” width x 20” height.
How much space do you need in front of a fireplace?
In front of a fireplace you need at least 16 inches of non-combustible material, known as the hearth. The hearth must also extend 8 inches past the firebox on each side.
What does a fireplace surround need to be up to code?
According to the National Fire Code, any combustible material like a wood fireplace surround must be at least 6 inches away from the firebox opening. It is recommended (but not required) to place the mantel at least 12 inches above the firebox opening to avoid the risk of fire.
