Standard Door Sizes: Width, Height, Thickness & How to Measure

Door dimensions are easy to recognize and easy to misapply. A listing that says 30 by 80 inches may describe the moving slab, while the project needs a complete prehung assembly. A wide opening between the trim may look ready for that assembly without revealing the framing behind it. Getting the right door begins with naming the dimension, then measuring the correct part.

Use this guide to compare common U.S. residential sizes, translate feet-and-inches notation and follow the measurement workflow for your project. It also explains how to plan a taller wood door, a custom opening or a different operating system without assuming every door follows the same sizing rule.

Standard door size chart: useful starting points

The dimensions below describe common product choices, not the only sizes a home can have. The Home Depot interior buying guide lists several stock widths and 80-, 84- and 96-inch heights. Its exterior guide identifies 36 by 80 inches as a familiar entry-door dimension. Availability varies by design, material and manufacturer.

Keep the chart beside your measurements rather than substituting it for them. A home can contain doors from different renovations, and a slab can have been trimmed. A familiar nominal size on a shopping page is a way to identify a product family; the specification and the existing conditions determine whether that product fits.

Standard door sizes in inches and millimeters

An 80-inch door is 2,032 mm tall. A 30-by-80-inch slab converts to 762 × 2,032 mm; a 36-by-80-inch slab converts to 914.4 × 2,032 mm. These are exact conversions of nominal U.S. dimensions, not a separate international sizing standard. Local stock sizes and the actual dimensions of a manufactured slab may differ.

For another height, 84 inches equals 2,133.6 mm and 96 inches equals 2,438.4 mm. Use the measurement tool above to convert your own readings. Keep any measured fractions instead of rounding them to the nearest stock size, and confirm whether the order calls for a slab or a complete frame.

What is standard door width?

There is no single width for every residential door. Interior widths such as 28, 30 and 32 inches are common starting points, and 36 inches is a familiar entry-door width. A closet or small utility opening may use a different arrangement. The room's function and the available space matter more than finding one average width for the whole house.

For an existing hinged door, measure the slab's actual width across its face, from edge to edge. That dimension is different from the distance between the jambs and from the decorative trim-to-trim measurement. If the door has a beveled edge, note it for the supplier; a straight-on photograph of the edge can clarify a reading that does not match a nominal label.

For a new opening, consider what must pass through it and how the room connects to the rest of the home. A furniture route, a frequent circulation path and a storage closet have different practical needs. Sketch the swing so a wider leaf does not interfere with another door, a cabinet or a fixture. Width affects both the closed opening and the space occupied by the open slab.

If access requirements apply, check the usable clear passage rather than the slab width alone. The open door and the frame occupy some of the opening. A nominally wide slab is not, by itself, proof of an accessible finished doorway. The clear-opening section below explains the distinction.

What is standard door height?

Many stock residential slabs are 80 inches tall, which equals 6 feet 8 inches. You will also encounter 84-inch doors, or 7 feet, and 96-inch doors, or 8 feet, in product lines that offer them. Calling a door standard describes a stock choice; it does not mean an older opening or a custom home must use that height.

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A taller door can change the proportions of a room, especially when it aligns with adjacent openings or other millwork. Evaluate it in elevation as well as on a floor plan. The head of the door, ceiling height, trim and any transom should work together. The slab's additional height also changes its hardware and support requirements, which the supplier must confirm.

When replacing a door, measure height from the slab's top edge to its bottom edge. When planning a complete assembly, agree with the installer on the floor or sill reference used for the required opening. Finished flooring, underlayment, thresholds and other installation details can change the available height. Record the reference beside the number so a measurement taken before flooring is not mistaken for a finished condition.

For a 36-inch-wide exterior entrance, compare 36 x 84 exterior doors and 36 x 96 exterior doors, then confirm the complete assembly and opening requirements. These dimensions describe individual door panels.

How to read door size notation

Door sizes can appear as inches, feet and inches, or abbreviated trade notation. A size written as 2 ft. 8 in. by 6 ft. 8 in. describes a nominal 32-by-80-inch slab. The multiplication sign means width by height. Thickness may appear as a third dimension, so read all the labels before transferring a number to an order.

Trade notation often separates feet and inches with a slash or combines them into a compact code. For example, 2/8 by 6/8 may represent 2 feet 8 inches by 6 feet 8 inches, rather than fractions of an inch. Formats vary, so confirm the supplier's convention. A plan tag or shorthand label does not tell you the unit's outside frame dimensions.

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Nominal means the stated or named size used to describe the product. Actual means the measured or specified physical dimension. The difference, if any, is product-specific. Do not assume every slab is undersized by the same amount, and do not round your existing slab before the supplier has reviewed the readings.

Slab size, frame size, rough opening and clear opening

These four measurements describe different parts of the same doorway. Slab size is the width, height and thickness of the moving door panel. Frame or unit size describes the outside dimensions of the complete assembly. Rough opening is the opening in the structural framing that receives the assembly. Clear opening is the usable passage when the door is open.

A prehung door is supplied with its slab mounted in a frame, with the included components determined by the product. That frame takes space beyond the slab. The rough opening also needs the installation allowance prescribed for the exact assembly. Exterior units add sill, weather-seal and other details that must be coordinated with the building.

Label sketches with the measurement endpoints. An unlabeled number such as 36 inches can mean any of several things during a renovation. A photograph that shows whether the tape touches the slab edge, the jamb or the framing is more useful than a measurement described only as the doorway width.

Never use a universal add-two-inches formula to convert a slab into a rough opening. Some products may have dimensions that resemble a familiar rule of thumb, but another assembly can use a different jamb, sill or installation detail. Obtain the manufacturer's required rough opening for the exact unit you intend to order.

How to measure when replacing only the slab

This workflow begins with the decision to keep the existing frame. Check that the jamb is suitable for reuse before ordering a matching slab. Loose hinges, distortion, deterioration or an incompatible stop arrangement can turn a simple replacement into a frame project. A new leaf cannot correct every problem in the opening that supports it.

1. Measure the slab width. Take edge-to-edge readings near the top, middle and bottom. Record the readings and identify any differences.
2. Measure the slab height. Measure from its top edge to its bottom edge at more than one location. Note trimming, damage or a nonuniform bottom.
3. Measure thickness at the edge. Use a clear area away from plates, hinges and applied trim. Do not measure a recessed panel.
4. Record the preparation. Photograph and measure the hinges, lock preparation and relevant locations. State where each location is measured from.
5. Record the operating arrangement. Sketch the hinges, latch side and direction of swing from a clearly identified viewpoint.

Keep the actual readings with the photographs rather than rounding everything to a familiar stock size. A slab measured just below 30 by 80 inches might belong to that nominal size family, or it might have been modified. The supplier and installer need to know which condition they are matching.

Matching width, height and thickness is only part of the work. Hinge mortises, corner shapes and lock preparation must agree with the existing jamb and selected hardware. The JELD-WEN slab instructions illustrate product-specific checks for frame condition and door preparation; their particular allowances are not universal specifications for other brands.

Do not trim a newly delivered door before checking the permitted trimming allowance for that model. Different constructions have different limits, and a glass or panel arrangement can restrict what can be removed. Confirm any required machining as part of the order so the new door's design and the old frame are coordinated.

How to measure for a complete prehung assembly

A prehung replacement needs measurements of the opening that receives the frame, not just the old slab. In an existing wall, the framing may be hidden by casing or other finishes. Have the installer establish the true rough opening rather than guessing from the visible trim. Masonite's interior measuring guide describes exposing and measuring the framing for its flat-jamb prehung workflow.

Measure the opening width at the top, middle and bottom. Measure height at both sides and near the center, using the agreed floor or sill reference. Record the readings, including the smallest available dimension. Then check the opening's diagonals, plumb and level. A large measurement at one location does not compensate for an opening that is skewed or twisted.

Next record the finished-wall depth and the relevant assembly conditions. For an exterior door, discuss the sill support, threshold and adjacent exterior finishes; the exterior door thickness guide explains how the slab and entry assembly work together. A brick or masonry opening can have its own dimensions and must not be assumed to equal the framed rough opening. Include photographs of both sides so the installer sees the surfaces the new frame must meet.

Compare those conditions with the exact product's required opening before finalizing the order. If they do not agree, the choices may include a suitable custom unit or a planned alteration of the opening. Let the installer evaluate the framing and finish work involved. The size printed on the old door does not resolve that decision.

Jamb depth and finished-wall thickness

Jamb depth describes the dimension through the wall that the jamb covers. It is not the width between the two side jambs. Finished-wall thickness includes the wall assembly and its finish layers. Casing is the decorative trim at the wall face. Keeping these terms separate prevents a correct slab size from being paired with an unsuitable frame.

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Measure the finished condition rather than selecting a jamb from the framing-lumber name alone. Wall finishes, tile, paneling or other layers can change the depth the frame must cover. If the two faces are not uniform, record that condition. Discuss extensions, trim and frame details with the installer instead of assuming casing will conceal every mismatch.

For terminology and frame parts, see our door jamb guide. For the moving panel's separate edge dimension, read the door thickness guide, which compares common 1⅜-, 1¾- and premium 2¼-inch wood options.

Clear opening: the passage you can actually use

A door's nominal width is not the same as its usable passage. For a hinged door, the open leaf and the stop affect the remaining clear opening. Handles, projecting hardware and the operating arrangement can also matter. Check this in the finished design, especially when changing thickness, using a pivot or selecting a pair of doors.

Where the ADA Standards apply, the U.S. Access Board guide explains a 32-inch minimum clear width and the measurement between the stop and the face of a swinging door opened 90 degrees. Other conditions and exceptions apply. A nominal 32-inch slab is not evidence of a compliant 32-inch clear opening.

Have the project designer confirm the requirements that apply to the particular opening. Clear width, maneuvering space, thresholds, hardware and operating conditions need to be reviewed together. Stock residential dimensions are product conventions; they do not replace accessibility, egress, fire-protection or other project requirements.

Double, barn, pocket and folding doors size differently

A double door contains two leaves, but adding their nominal widths does not establish the complete unit dimension. Confirm the active leaf, the meeting arrangement, the frame and how the pair is used. If everyday access is through one leaf, evaluate that passage rather than only the total opening when both leaves are open.

A barn door runs along the wall face and generally covers an opening instead of swinging within a conventional jamb. Its sizing must account for the selected overlap, travel, guides, mounting and handle clearance. A pocket door enters a wall cavity, so the pocket frame and hardware determine the space and slab dimensions. Folding panels stack and use another set of clearances.

Use the instructions for the actual system rather than transferring a hinged-door formula to it. Our barn-door measuring guide develops the overlap and travel checks, while the pocket-door hardware guide covers pulls and operating functions. Rustica offers barn doors and interior door options for different arrangements. Compare the door and its supported hardware as one project.

Three examples of reading a size correctly

Imagine an existing bedroom slab that measures just below a familiar 30-by-80-inch size. Those measurements identify the leaf you have; they do not reveal whether the slab was originally undersized or later trimmed. For a slab replacement, preserve the actual readings and preparation. For a complete replacement, measure the receiving opening separately.

Now consider a product described as a 36-by-96-inch wood entry door. That description communicates nominal width and height, but the order still needs the actual slab, complete frame, jamb depth, sill and required rough opening. A taller label does not tell an installer where the structural header must be placed.

Finally, consider two nominal 30-inch leaves. Their widths help describe the pair, but the meeting detail and surrounding frame determine the full unit. The clear passage with only one active leaf open is another measurement. These examples show why one attractive size label cannot answer every installation question.

When a custom size is the right conversation

An opening outside a stock size is a reason to investigate, not immediately to rebuild the wall. First establish whether the existing frame is sound and whether the project replaces only the slab or the whole assembly. Then compare an appropriately specified custom door with altering the opening, including the installation and finish work each path requires.

Custom sizing also offers a way to coordinate proportions in a new design. Width, height, panel layout and wood character should be reviewed together rather than treating a door as a standard slab stretched to fit. Confirm the available size range, hardware support and preparation for the chosen model before approving the final drawing.

If you are considering a substantial wood profile, our 2¼-inch thick wood-door guide explains that option. Its thickness must be coordinated with the frame and compatible hardware; it does not change the need for accurate width and height measurements.

Once the measurement type is clear, shop Rustica doors by width and height to compare designs in the proportions you want. If the opening needs another dimension, use the custom-size door guide and share the existing readings, preferred model and replacement scope with Rustica. The goal is a door that fits both the opening and the architecture, with its final dimensions confirmed before fabrication.

Sizing mistakes to avoid before placing an order

The most useful check is to ask what each number actually measures. Do not transfer a trim-to-trim reading to a rough-opening field, or use a nominal slab label as the outside frame dimension. Keep the original measurements and their endpoints visible until the supplier and installer agree on the specification.

Another common problem is measuring before the floor and finishes are settled. A door that clears the subfloor may encounter the planned finish flooring. A jamb selected before wall finishes are included may not cover the final depth. Record the existing and planned conditions separately so the design accounts for the finished installation.

Finally, confirm preparation and swing instead of checking only width and height. A matching slab can still have incompatible hinges or lock locations. A well-sized assembly can still swing into a fixture. A sketch and a few clear photographs usually communicate these conditions more effectively than an unlabeled list of numbers.

Standard door size questions

Is a standard door 80 inches tall?

Many stock U.S. residential slabs are 80 inches tall. That is a common product height, not a universal requirement. Other offered heights include 84 and 96 inches, and existing or custom doors may differ. Measure the slab or use the exact assembly specification for your project.

What is the standard bedroom door size?

Widths such as 28, 30 and 32 inches by 80 inches high are common starting points for interior doors, but a bedroom does not have one universal slab size. Match the opening, intended access, frame and applicable project requirements. Confirm thickness and preparation as well as width and height.

What rough opening do I need for a 36-inch door?

Use the required rough opening for the exact prehung assembly. A 36-inch label usually identifies slab width; it does not provide the outside frame dimension or installation allowance. Jamb, sill and frame designs vary, so do not apply one add-on formula to every product.

Does 2/8 by 6/8 mean 32 by 80 inches?

In common feet-and-inches door notation, yes: 2 feet 8 inches equals 32 inches and 6 feet 8 inches equals 80 inches. Confirm the supplier's notation and whether the dimensions are nominal or actual. They do not automatically describe the complete frame.

Can I keep the old frame when changing door size?

Only if the proposed slab and preparation suit that frame and the installer confirms its condition and clearances. A different width, height or thickness may require frame changes or a complete replacement. Establish the replacement path before ordering the slab or hardware.

Bring these details to your door consultation

Bring the measured slab dimensions when it is being reused as a reference, the labeled opening measurements, finished-wall depth, photographs and a swing sketch. State whether you want a slab or a complete assembly, and identify any existing hardware you hope to keep. For a new build, include the planned opening and the selected product's specification.

With that information, you can discuss both fit and design: a matching replacement, a taller wood door or a custom assembly. Contact Rustica to explore the appropriate options, then have the supplier and installer confirm the final dimensions and preparation before the order is placed.

Sources and further reading

• The Home Depot: Interior Door Buying Guide — common stock residential widths and heights.
• The Home Depot: Exterior Door Buying Guide — common entry dimensions and exterior frame terminology.
• Masonite: Measuring for an Interior Door — a manufacturer workflow for a flat-jamb prehung interior assembly.
• JELD-WEN: Interior Door Slab Installation Instructions (JII110) — examples of product-specific frame and preparation checks.
• U.S. Access Board: Entrances, Doors and Gates — clear opening and other requirements where the ADA Standards apply.
• Rustica: Altitude Interior Door — source of the design-example photograph.