Window Trim Linear Feet Calculator
Free Window trim linear feet Calculator for home & garden projects. Enter dimensions to get material lists and cost estimates.
Formula
Linear Feet = (2 x Width + 2 x Height) x Number of Windows
For full surround trim, add twice the width and twice the height of each window opening (in feet) to get the perimeter. Multiply by the number of windows. Add 10% for cutting waste. For three-sided trim, use one width plus two heights per window.
Worked Examples
Example 1: Full Surround on 8 Windows
Problem: Calculate linear feet for 8 windows, each 36 inches wide and 48 inches tall, with full surround trim.
Solution: Width in feet = 36 / 12 = 3 ft\nHeight in feet = 48 / 12 = 4 ft\nPerimeter per window = 2(3) + 2(4) = 14 ft\nTotal = 14 x 8 = 112 ft\nWith 10% waste = 123.2 ft
Result: 123.2 linear feet of trim needed
Example 2: Three-Sided Trim for 5 Windows
Problem: Calculate trim for 5 windows, 30 inches wide by 60 inches tall, three-sided style.
Solution: Width = 30 / 12 = 2.5 ft\nHeight = 60 / 12 = 5 ft\nPer window = 2.5 + 2(5) = 12.5 ft\nTotal = 12.5 x 5 = 62.5 ft\nWith 10% waste = 68.75 ft
Result: 68.75 linear feet of trim needed
Frequently Asked Questions
How do I measure linear feet of window trim?
Measure each side of the window opening where trim will be installed. For a full surround, measure the width at top and bottom and the height on both sides. Add all four measurements together for one window. Convert inches to feet by dividing by 12, then multiply by the number of windows to get total linear feet needed.
How much extra trim should I buy for waste?
Plan for 10 percent extra material to account for cutting waste, mitered corners, and mistakes. If you are new to trim installation, consider adding 15 percent instead. Trim boards come in standard lengths of 8, 10, 12, and 16 feet, and the offcuts from each piece may not always be reusable depending on the window sizes.
What is three-sided window trim?
Three-sided trim, also called casing, covers the top (head casing) and both vertical sides (jamb casings) of the window. The bottom is left open for a window sill or stool. This is the most common residential trim style. Full surround trim adds a fourth piece along the bottom, often called an apron, for a more finished look.
What are common window trim widths and materials?
Standard window casing is 2.25 to 3.5 inches wide. Popular materials include finger-jointed pine for painted trim, solid pine or poplar for stain-grade, and MDF for budget-friendly painted applications. PVC and composite trim work best for exterior use since they resist moisture and insects without requiring painting.
What formula does Window Trim Linear Feet Calculator use?
The formula used is described in the Formula section on this page. It is based on widely accepted standards in the relevant field. If you need a specific reference or citation, the References section provides links to authoritative sources.
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.