Weatherstripping Calculator

Estimate how much weatherstripping to buy to seal doors or windows. Enter the size and quantity to get the linear feet, door sweeps, and optional material cost.

weatherstripdoor sweep
Weatherstripping to Buy
ft
Perimeter strip with a 10% waste allowance.

Usage Tip

Clean and dry the surfaces before applying adhesive-backed weatherstrip, and replace compressed or cracked strip rather than layering over it. Buy one continuous roll per opening where you can to avoid seams.

THE MATH
Door perimeter strip = 2 × Height + Width (top and both sides)
Window perimeter = 2 × (Width + Height)
Buy = total × 1.10, rounded up (10% waste)
Doors get weatherstrip on the top and two sides; the bottom is sealed with a separate door sweep, so the bottom is not counted in the perimeter strip.
Windows are sealed around the full perimeter.
Linear feet are based on the opening size you enter; measure the actual jamb if it differs.
Compression strip (V-strip, foam, or kerf-in) and the door sweep are sold separately — this counts the strip length and the number of sweeps.
Add a little extra for trimming and corners; the 10% waste allowance covers typical offcuts.
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The calculators and tools on Formula Factory are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. Formula Factory makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.