Selecting the perfect fireplace mantel requires accurate measurements. This guide will help you measure your fireplace mantel. It includes tips, tricks, and answers to common questions. This way, you can get it right the first time.

Many measures will help you get the right fit. Here are the three most important tips to help you learn how to measure for a fireplace mantel shelf or how to measure for a fireplace mantel surround.

1. Measuring the Height of Your Fireplace Mantel

Height is one of the key elements that determine the overall proportion of your mantel and how it fits in your space.

  • Start by measuring from the floor up to 4.5 feet (standard height for a mantel). That’s a good starting place from which to determine how far up your mantel should go.

  • If you have a surround or a linear fireplace placed higher on the wall, consider raising your mantel. It may be best to have it more than 4.5 feet off the ground. You may also want the mantel to overlap the surround or facing. If so subtract a half inch from your measurement to ensure overlap.

  • If you have high ceilings, you also might want to consider a mantel placed above 4.5 feet to balance the room.

  • If you choose a mantel with legs, take off half an inch from your height measurement. This will create an overlap of the mantel and the fireplace surround or facing material, which ensures the fireplace looks cohesive.


Pro Tip: Make sure you have at least a foot of space between the top of your fireplace and the mantel for a good balance. Also check the manufacturer directions on your fireplace and local codes to see minimum recommendations for clearance.

 

Mantel Dimension Diagram

A - Overall Height
B = Opening Height
C = Opening Width
D = Overall Fireplace Mantel Shelf Length
E = Body Width
F = Fireplace Mantel Shelf Depth
G = Return Depth (Cavity Behind Mantel)
X = Leg Width
Y = Leg & Shelf Overhand
Z = Breast Height

Mantel Shelf Length Restrictions

B: Facing Height minus 1/2 inch
C: Facing Width minus 1 inch
G: Return Depth Equals Facing Thickness plus 1/4 inch

2. Measuring the Width of Your Fireplace Mantel

The mantel's width is essential for achieving visual balance. A good rule of thumb is that the mantel should be 3-6 inches wider on each side (a total of 6-12 inches wider).

  • Measure the full width of the firebox opening. Add at least 6 inches to each side for proper mantel shelf width. For example, if your firebox opening is 40 inches, a mantel shelf at least 52 inches wide will work best.

  • If you have a surround or facing, measure from the outside the surround/facing instead of the firebox.

  • A mantel kit/package or mantel with attached legs, measure from the outside the firebox for the correct proportions. Be mindful of maintaining overlap on each side if you have a surround/facing around your firebox.

  • Keep in mind any width restrictions such as if the fireplace is between a window and door. Be sure the mantel is not so wide it gets too close to these other features.


Pro Tip: You can extend the shelf width to make a bold design statement but ensure it doesn’t overpower your room’s size.

3 . Measuring the Depth of Your Fireplace Mantel

The depth is how far the mantel shelf will project out from the wall.

  • Begin by measuring from the wall to the front of your existing fireplace surround (or firebox opening). Typically, mantels project 6 to 12 inches from the wall.

  • If you have a recessed fireplace, the depth measurement may be minimal to none. If you have a bump out, make your mantel deeper than the bump out, unless you plan to place the mantel on the bump out as well.


Pro Tip: Consider how much room you need for decor items like picture frames or holiday decorations. You’ll want enough space to accommodate these without blocking the view or protruding too far into the room.

Sierra Flame Thompson 36-in Direct Vent Gas Fireplace THOMPSON-36-DELUXE

4. Other Measurements

If you are measuring for custom elements, your customer service representative may ask you for additional measurements to ensure a good fit. You can see those in the chart. We will draw attention to one other important measurement you’ll need to plan around: return depth.

Return depth is the distance between the face of the fireplace and the wall. The face of the fireplace may be brick, slate, or some other non-combustible material that you want to cover up in a fireplace remodel. And it may cause your mantel to stand out from the wall a bit creating a gap. This gap can be covered with some scribe molding.

  • For return depth, measure from the wall to front of the face of the fireplace.
  • Add ¼ inch to this measurement and you have the return depth. For instance, if you have ¾ inch marble on the face of your fireplace, add ¼ inch to that and you have 1 inch as the return depth measurement.


Pro Tip: Some designs use a shadow box look in which uses a deeper return to create a somewhat recessed appearance to the fireplace. Advise your rep that this is your goal so they can provide a deeper scribe molding.  

 

Salem Wood Mantel Shelf in Cherry Stain

Frequently Asked Questions About Measuring for Fireplace Mantels

Q: What is the standard height for a fireplace mantel?
A: There isn’t a strict “standard” height, but the average mantel shelf is installed about 54-60 inches above the floor. If you have higher ceilings, you may want to raise it to create balance. Always ensure you maintain the minimum clearance from the firebox per local building codes.

Q: How far should a mantel stick out?
A: A depth of 6-12 inches is typical. However, this depends on your design preferences and the size of the room. A smaller room might benefit from a shallower mantel to avoid overcrowding the space.

Q: How much wider than the firebox should the mantel shelf be?
A: Your mantel shelf should extend at least 3-6 inches beyond the edges of the firebox on each side. This provides visual balance and ensures it doesn’t appear undersized for the fireplace opening.

Q: What is code for distance between the fireplace and mantel?
A: Nationally, the average is 6 inches. However, check local codes to ensure you are compliant.

Q: Can I use my mantel shelf without a fireplace?
A: Yes! Mantel shelves make great floating shelves for displaying decor in various parts of your home. If you’re using it outside of the fireplace setting, focus more on proportion to the wall and room rather than firebox measurements.

Q: Should I leave extra space around my mantel for decor?
A: Definitely. If you’re planning on hanging a mirror, TV, or artwork above your mantel, be sure to account for this in your height measurements. Additionally, leave enough shelf space for any items you want to display, keeping in mind the shelf’s depth.

Q: How high should a TV be above the mantel?
A: It all depends on the height of your mantel, but the range is from 4 to 12 inches. If your mantel is over 4.5 feet off the ground, hang your TV no more than six inches above the mantel.

Q: How much wider should a mantel be than a TV?
A: The TV should be narrower than the mantel. A good rule of thumb is to have the TV be 30% narrower than the mantel.

Q: How far off the mantel should I hang a mirror or art?
A: It’s all about perspective and taking in the dimension of the room. Designers often suggest that you have about 66% of your wall space open above the top of your mirror or art and 33% open below (including the mantel and fireplace)

By following these easy measuring instructions and tips, you will choose a fireplace mantel that fits your space well. When in doubt, consult a professional. Our team is standing by to help out.

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