Fireplace doors · Measuring guide
Measure the opening.
Keep every number.
Six measurements, a few photos, and the details that help us get your door right. Start here before choosing a size.
01 · Get ready
A tape measure, a phone, and a cold fireplace.
Find the actual opening
The opening is the space the new door will cover or sit inside. The old trim, decorative surround, and glass panels are different measurements. Photograph them, but do not substitute their size for the opening.
If an existing frame hides the edges, send a photo first. Leave installed parts in place until the removal method is confirmed.
Know what you are measuring
For a factory-built fireplace, write down the brand and full model number first. Its manual and the chosen door determine the mounting points. A sealed gas fireplace needs its own approved front or replacement glass.
Help me identify my fireplace →Use inches and record the actual reading, including fractions. For example, 36⅛ inches can be written as 36 1/8 or 36.125. Do not add overlap or subtract a fitting allowance yourself.
02 · Record the opening
Three widths. Three heights.
These are preliminary measurements for a rectangular opening. Keep the tape straight, in the same front measuring plane for each reading. Your chosen door’s worksheet takes priority if it specifies different measuring points.
Width: top, middle, bottom
W1 = top · W2 = middle · W3 = bottom. Measure from the inside left edge to the inside right edge. Record each position separately. Check for an edge that narrows behind the face, especially with an inside-fit door.
Height: left, center, right
H1 = left · H2 = center · H3 = right. Measure vertically from the bottom surface where the frame would sit to the underside of the opening. Note any steel lintel or projection that makes a lower point.
Photograph anything in the way
Include raised stone, a sloping hearth, old tracks, handles, vents, and controls near the frame. A straight-on photo and an angled close-up show different things.
See the tape positions
Keep the tape straight and read between the opening edges. These examples show the direction of the measurement; record your own readings at all six positions shown above.
Measuring a factory-built fireplace?
Identify the fireplace brand and model first. Do not use the outside trim as the opening size, and do not remove installed parts to copy an example photo.
My opening is arched, angled, or uneven
Record the full width, the height at each side, and the center height. Send a straight-on photo before drawing a template or selecting a door size. An arch, corner fireplace, or opening with a projecting stone may need a model-specific drawing.
Request help with an unusual opening →03 · Check the mounting area
Inside fit and overlap need different space.
Inside fit: check inside the opening
The frame sits within the opening. Check the usable depth at the intended mounting plane and any inward-projecting brick, lintel, old hardware, or uneven sides.
Send: all six readings, a photo of each inside edge, and a side view showing available depth. Tell us where you held the tape.
Overlap: check around the opening
The frame extends onto the face around the opening. Check the flat, usable space at the top and sides, and the way the bottom meets the hearth. Raised stone can prevent a frame from sitting evenly.
Send: all six readings, the available face width on each side, and photos of the hearth and any nearby vents or trim.
For prefab fireplaces, airflow openings and access to controls must remain as specified by the appliance manufacturer. Inside fit is not automatically correct just because the fireplace is prefab.
04 · Keep a record
Your measuring notes
Optional: enter your readings here and copy the notes for your consultation. This does not calculate a finished door size or send an order.
Widths, in inches
Heights, in inches
Notes stay on this page. Copy them before leaving; they are not saved to your account or added to checkout.
Ready for a second look?
Send the six readings, a straight-on photo of the whole fireplace, an angled photo of the opening and hearth, and a readable model-label photo if there is one. Include the door style you like and whether the surround is finished or still being built.
Every order is reviewed by our fireplace specialists. If you are using our Fit Guarantee, review its required measurement verification and photos before production.
Measuring references
Design Specialties: measuring an opening for stock doors. Final measuring points and allowances come from the selected door’s instructions; this worksheet records your opening without applying a deduction.