--- title: "Window & Door Sizing Calculator: Estimate Openings & Materials" description: Easily find the right fit for your next project with LS Building Products' Window & Door Sizing Calculator. Quick, accurate measurements for contractors and builders. image: https://ls-usa.com/hubfs/Gemini_Generated_Image_sdxxecsdxxecsdxx%20(1).png --- [![LS Building Products](https://ls-usa.com/hs-fs/hubfs/Logo%20(13).png?width=98&height=67&name=Logo%20(13).png) ](https://ls-usa.com/) [ Get A Quote ](https://ls-usa.com/contact) ![Open](https://ls-usa.com/hs-fs/hubfs/Shape%201%20(4).png?width=31&height=26&name=Shape%201%20(4).png) ![close](https://ls-usa.com/hs-fs/hubfs/close-circle-fill.png?width=28&height=28&name=close-circle-fill.png) [ Get A Quote ](https://ls-usa.com/contact) ![LS Building Products ](https://ls-usa.com/hubfs/BG%20image.webp) ![LS Building Products ](https://ls-usa.com/hubfs/BG%20image.webp) # Window & Door Sizing Calculator Easily determine the correct size for your windows and doors with our sizing calculator. Simply input your measurements and specifications to get the accurate dimensions you need for a perfect fit. [![Explore Windows & Doors](https://no-cache.hubspot.com/cta/default/22146047/dc96ceb1-5c93-41b9-afa7-625eebea434d.png)](https://cta-redirect.hubspot.com/cta/redirect/22146047/dc96ceb1-5c93-41b9-afa7-625eebea434d)   --- ## Window & Door Sizing Calculator ### Instructions  Enter inches as decimals (e.g., 23.5). Choose your known dimension, then width and height. Adjust shim and sealant gaps to your spec. Select a profiled casing and optional sill nosing. Click “Calculate”. #### Calculate using known Rough Opening Overall Unit Size Casing Dimensions Masonry Opening #### Width (in inches)* #### Height (in inches)* #### Shim Space (in inches)* #### Sealant Gap (in inches)* #### Profiled Casing A753 #### Sill Nosing None A751 A752 Calculate Reset calculator ↻ ### Results: | Options Selected | | | --- | --- | | Calculate Using Known | — | | Width (in inches) | — | | Height (in inches) | — | | Shim Space (in inches) | — | | Sealant Gap (in inches) | — | | Profiled Casing | — | | Casing Size | — | | Sill Nosing | — | | Sill Nosing Size | — | | Calculated Dimensions | Width | Height | | --- | --- | --- | | Overall Unit Size | — | — | | Rough Opening | — | — | | Casing Dimensions | — | — | | Masonry Opening | — | — | --- *This calculator is for general informational purposes only. Please verify all results with a licensed contractor, as actual project requirements may vary.* ## **Key Features** **✔ Clear, contractor-friendly UI** with inputs for the known dimension, finished width/height, shim space, sealant gap, casing profile, and optional sill nosing. **✔ Start from what you know** — calculate from *Rough Opening*, *Overall Unit Size*, *Casing Dimensions*, or *Masonry Opening*, and the tool derives the rest. **✔ Accurate add-ons** using per-side casing adds (L/R/T/B) and sill nosing overrides for precise finished sizes. **✔ Instant, consistent results** showing *Overall Unit*, *Rough Opening*, *Casing*, and *Masonry* dimensions side-by-side (Width & Height). **✔ Print-ready output** with a single click to share specs with installers, suppliers, or clients. ## **How to Use It** 1. **Choose your starting point:** Select *Rough Opening*, *Overall Unit Size*, *Casing Dimensions*, or *Masonry Opening* under “Calculate using known”. 2. **Enter Width & Height:** Type the values in inches (decimals like `23.5` are OK). 3. **Set gaps:** Enter *Shim Space* and *Sealant Gap* to match project requirements. 4. **Select trim options:** Pick a *Profiled Casing* and (if used) a *Sill Nosing*. The calculator applies the correct side/top/bottom adds. 5. **Review results:** Click **Calculate**. The right panel lists *Overall Unit*, *Rough Opening*, *Casing*, and *Masonry* dimensions (Width & Height). 6. **Print or reset:** Use **Print** to save/share the spec sheet, or **Reset calculator** to start fresh. ### **Size Windows & Doors with Confidence** This calculator removes guesswork by converting between unit size, rough opening, casing, and masonry dimensions with the correct allowances for shims, sealant, casing profiles, and sill nosing. Specify once, get every related dimension instantly, and send accurate cut sheets to the field or your supplier. ### Questions about any of our products? We're ready to help you find a solution! 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