--- title: How to Resize a Door Opening description: "On this page[Introduction](#)[Before You Begin](#)[Prerequisites](#)[What You Need To Know](#)[Tools](#)[Materials](#)[Installation Steps](#)[Step 1. Measure and Mark the New Opening](#)[Step 2. Remove Existing Framing](#)[Step 3. Cut and Install the New Header](#)[Step 4. Frame the New Opening](#)[Step 5. Install the Door Jamb](#)[Pro Tips](#)[Common Mistakes](#)[QC…" url: "https://letsbuildstuff.co/learn/resize-a-door-opening/" updated: "2026-09-26" category: "Doors & Openings" tags: - Core Guide - Level 2 --- # How to Resize a Door Opening On this page[Introduction](#)[Before You Begin](#)[Prerequisites](#)[What You Need To Know](#)[Tools](#)[Materials](#)[Installation Steps](#)[Step 1. Measure and Mark the New Opening](#)[Step 2. Remove Existing Framing](#)[Step 3. Cut and Install the New Header](#)[Step 4. Frame the New Opening](#)[Step 5. Install the Door Jamb](#)[Pro Tips](#)[Common Mistakes](#)[QC / Punch Checklist](#)[Related Guides](#) [Doors & Openings](/learn-category/doors/) Skill Level: [Intermediate (Level 2)](/learn/difficulty-levels/#level-2) · Estimated Time: 45-60 Minutes Per Opening ## Introduction Resizing a door opening is a crucial task in both new construction and remodel projects, and when you resize a door opening the framing has to end up as if it had been built that way from the start. Header sizing follows the plans, or the span tables in [IRC Chapter 6, Wall Construction](https://codes.iccsafe.org/content/IRC2021P2/chapter-6-wall-construction), when the plans are silent. Whether you're accommodating a new door size or adjusting for a different style, resizing ensures a perfect fit and smooth operation. This task often comes into play when replacing doors or updating the layout of a space. The single most important concept to master is precision in your measurements and cuts. A miscalculation can lead to a door that doesn't fit properly, resulting in time-consuming adjustments and potential callbacks. In the fast-paced world of new construction, efficiency and accuracy are paramount. Establishing a standard charge per opening, as suggested by Joel, can streamline your invoicing process and ensure consistent pricing for your services. Remember, the key to professional results lies in your ability to execute clean, precise cuts and maintain structural integrity throughout the process. ## Before You Begin Before you resize the door opening, confirm that the following prerequisites are complete. ### Prerequisites - Drywall removal in the area of the door opening - Flooring installation in adjacent areas is complete - All [rough-in](/glossary/business/#rough-in-trim-out) work, such as electrical or plumbing, that intersects with the door location is finished ### What You Need To Know When you resize a door opening, understanding these core techniques will save you time and prevent callbacks. - Ensure the header and jack studs are correctly positioned and secure to maintain structural integrity - Consider the final door swing and hardware placement to avoid conflicts with existing structures - This guide is for an interior wall opening only. An [exterior or house to garage opening](https://letsbuildstuff.co/learn/install-exterior-door/) is a different job and is not covered here. ## Tools - [Circular Saw](/glossary/tools/#circular-saw) - for cutting through studs and headers - Reciprocating Saw - useful for cutting nails and making precise cuts in tight spots - Level - to ensure the new opening is [plumb](/glossary/layout-and-shop-talk/#plumb-level-square-condition) and level - [Framing Square](/glossary/tools/#framing-square) - for accurate measurements and ensuring square corners - Hammer and [Pry Bar](/glossary/tools/#pry-bar-flat-bar) - for removing existing framing and nails ## Materials - 2x4 or 2x6 Lumber - for framing, depending on wall thickness - Header Material - typically a doubled 2x6 or 2x8, depending on span and load - Shims - to adjust the fit of the door jamb ## Installation Steps ### Step 1. Measure and Mark the New Opening Determine the new dimensions required for the door and mark the existing wall accordingly. Ensure you account for the door jamb and any additional trim. - Use a level and framing square to mark straight lines - Double-check measurements before cutting ### Step 2. Remove Existing Framing Carefully remove the existing door frame and any necessary wall materials to expose the studs and header. - Use a reciprocating saw to cut through nails and screws - Preserve any materials that can be reused ### Step 3. Cut and Install the New Header Cut the new header to size and install it above the door opening, ensuring it is level and properly supported by jack studs. - Secure the header with nails or screws appropriate for the load - Check for level and adjust as necessary ### Step 4. Frame the New Opening Install new king and jack studs to frame the sides of the door opening. Ensure everything is plumb and square. - Use a level to ensure vertical alignment - Secure studs with appropriate fasteners ### Step 5. Install the Door Jamb Fit the door jamb into the new opening, using [shims](/glossary/tools/#shims-cedar) to ensure a snug and level fit. - Nail the jamb at each shim point with a 15-gauge finish nailer, checking for plumb and level - Trim shims [flush](/glossary/layout-and-shop-talk/#flush) with the jamb once secured ## Pro Tips **Pro Tip:** Consider resizing openings when drywall has been removed to simplify the process and reduce extra work. ## Common Mistakes - **Mistake:** Incorrect header size - Ensure the header is sized appropriately for the span and load to avoid structural issues. - **Mistake:** Misaligned door jamb - Use shims and a level to ensure the door jamb is plumb and square, preventing door operation issues. - **Mistake:** Insufficient insulation - Failing to insulate around the door frame can lead to drafts and energy loss. ## QC / Punch Checklist - Verify the door opening is square and plumb - Check that the door jamb is securely fastened and level - Confirm the new framing is plumb, the header is bearing fully on the jack studs, and the rough opening is sized to the new jamb. - Confirm the door swings freely without obstruction ## Related Guides - [How to Install a Pre-Hung Door](https://letsbuildstuff.co/learn/install-pre-hung-door/) - [How to Install a Cased Opening](https://letsbuildstuff.co/learn/install-cased-opening/) - [How to Install an Interior Center-Opening or French Door](https://letsbuildstuff.co/learn/interior-center-opening/) - [How to Install a 6'8" Cased Opening](https://letsbuildstuff.co/learn/install-6-foot-8-inch-cased-opening/) - [How to Case One Side of a 6'8" Door](https://letsbuildstuff.co/learn/case-one-side-door-68/) --- ## Reference Photos The following photos show examples of this type of work completed in the field. These serve as visual references for quality standards, proper installation techniques, and finished results. Showing 1 of 1 photos [![Unfinished door opening with red marker outlining the jamb, framing marked for resizing](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240306_144514-225x300.jpg)](https://letsbuildstuff.co/website_ad59d41f/wp-content/uploads/2026/03/20240306_144514.jpg) Unfinished door opening with red marker outlining the jamb, framing marked for resizing × ‹ › Written by **David Hospodka**, Sun’s Up Construction David Hospodka learned finish carpentry from his father, alongside his brother Joel, and worked his way through college trimming houses. He then spent about ten years as a railroad bridge engineer, handling design, construction, maintenance and project management. He came back to finish carpentry full time in 2017. [About Let’s Build Stuff](https://letsbuildstuff.co/about/)