Things to consider when determining the depth of your mantel:

• The amount of usable space you would like to have on the top for decorations
• How far out you would like your mantel to protrude from the wall
• If your mantel is going to be installed onto drywall that will later have stone or brick installed around it, we recommend increasing the depth of your mantel to accommodate the area that will be obstructed by the stone/brick.  Example:  If you order a 6" deep mantel and your stone/brick protrudes from the wall by 2", your usuable mantel depth will only be 4".
• The depth of your mantel will also determine the distance you will need to have between your firebox and the bottom of the mantel.  The farther your mantel protrudes from the wall, the larger the distance it will need to be from the firebox.  Please see the Firebox Distance section below for more information.

Things to consider when determining the height of your mantel:

• The height of the individual stone/brick/tile behind your mantel.  Example:  If the stone pieces behind your mantel are 6" in height, then you may want your mantel to be of similar height, so as to create clean visual lines when viewed from afar.
• You want the height of your mantel to be relative to its depth and length.  A good rule of thumb is to not make the height any less than half of its depth.  Example:  If your mantel depth is 10", you do not want the height to be any less than 5".  Otherwise you run the risk of the mantel looking thin and chunky, and visually making it look out of balance.

A full length mantel extends fully from one side of the fireplace face to the other.  This type of mantel is common when your fireplace is surrounded by other architectural elements, such as built-in cabinets or bookshelves.  The overall look is one that is more dominant and commanding.

The most common type of mantel length, an equidistant mantel is one that is centered inside the face of the fireplace and has an equal and proportional area of stone/brick/tile around the sides of it.  

There is no set rule for how much space to leave at the sides of your mantel.  It all comes down to your personal style and preference for the space the mantel will occupy.  Your main consideration should be to create a mantel that balances the overall look of your fireplace and not overwhelm it.  

A mantel that is the same length as the firebox below it will give a more minimal and streamlined look and feel to your fireplace.  This type of mantel is most commonly seen in rooms with smaller spaces or with another focal point besides the fireplace, such as a bay of windows.