A door rough opening calculator gives you the exact framed opening dimensions before you start swinging a hammer. Enter your door size, type, and framing material, and instantly get the rough opening width and height, recommended header size, jack stud length, king stud length, and cripple stud count — everything your framing crew needs on one sheet.
Door Specifications
Standard 8ft wall = 97.125"
Full Framing Details
How to Use the Door Rough Opening Calculator
Getting the door rough opening size wrong means shimming an overly tight frame or filling an overly large gap with extra blocking. This door rough opening calculator removes the guesswork — select your door type, enter the slab dimensions, and receive complete framing dimensions including rough opening, header size, and stud lengths.
Step 1: Select the Door Type
Choose from interior, exterior, pocket, barn/sliding, or bifold. Each type has different rough opening allowances. Interior pre-hung doors need 2" of extra width and height for shimming. Exterior doors need slightly more. Pocket doors require a rough opening twice the door width plus hardware clearance. The calculator applies the correct formula for each type.
Step 2: Enter Door Dimensions
Use the quick-pick buttons for standard sizes (24"–36" wide, 80"–96" tall) or type custom dimensions. Toggle to metric (cm) if needed. Standard residential door height is 80" (6'8"). Taller 84" and 96" doors are common in new construction with higher ceilings.
Step 3: Set Framing Type and Wall Height
Choose wood or metal stud framing. Enter the overall wall height — a standard 8-foot ceiling uses 97 1/8" tall studs (the extra 1/8" accounts for the top and bottom plates). The calculator uses wall height to determine cripple stud length — the studs that fill the space between the header and the top plate.
Step 4: Read the Results
The results show rough opening width, rough opening height, jack stud length (the trimmer studs that carry the header), recommended header size by span and load type, and cripple stud count. The notes panel provides application-specific reminders — for example, pocket door hardware requirements and load-bearing header size caveats.
Frequently Asked Questions
Is this door rough opening calculator free?
Yes, the door rough opening calculator is completely free with no usage limits. All calculations run locally in your browser — no signup, no account, and no data ever leaves your device.
Is my project data private?
Yes, everything is calculated in your browser. Your door dimensions and project details are never sent to any server or stored remotely.
What is a rough opening for a door?
A rough opening is the framed hole in the wall that the door unit (door slab plus frame) fits into. It is always larger than the door itself to allow for the door frame, shimming, and plumbing. A standard interior door rough opening is 2 inches wider and 2 inches taller than the door slab size.
How much bigger is the rough opening than the door?
For standard pre-hung interior doors, the rough opening is typically 2 inches wider and 2 inches taller than the door slab. For example, a 32" × 80" door needs a 34" × 82" rough opening. Exterior doors often require 1/2" more on each side (so 3" total width, 2.5" total height) for weatherstripping and thicker frames.
What size header do I need for a door?
Header size depends on the span and load. For non-load-bearing walls, a single 2×4 on the flat or a doubled 2×4 is sufficient. For load-bearing walls, span determines the size: up to 3' span use doubled 2×6; 3'–5' use doubled 2×8; 5'–7' use doubled 2×10; 7'–9' use doubled 2×12. Always consult local building codes and a structural engineer for load-bearing applications.
What are jack studs and king studs?
King studs run the full height from bottom plate to top plate on each side of the opening. Jack studs (also called trimmer studs) sit inside the king studs and support the header — they are cut to the height of the rough opening. Cripple studs fill the space between the header and the top plate.
How do I frame a rough opening for a pocket door?
A pocket door rough opening must be twice the door width plus approximately 1 inch for the pocket kit hardware, and the same height as a standard door rough opening. The pocket kit frame is installed within this opening before drywall. Because pocket doors require a thicker wall, ensure your wall is at least 3.5" deep (standard 2×4 framing).
What is shim space and why does it matter?
Shim space is the gap between the door frame and the rough opening framing — typically 1/2" per side in width and height. This space allows you to level, plumb, and square the door frame perfectly, regardless of minor imperfections in the framing. Without shim space, the door frame would jam against out-of-plumb framing and the door would not operate properly.