Weatherstripping Calculator
Calculate total linear feet of weatherstripping for all doors and windows.
Returns lengths with recommendations for foam tape, V-strip, and door sweeps.
Weatherstripping seals gaps around doors and windows to prevent air infiltration, moisture intrusion, and heat loss. Properly installed weatherstripping can reduce heating and cooling costs by 10–20% according to the U.S. Department of Energy.
Total length formula: Door Weatherstripping = 2 × Door Height + Door Width (top + two sides; threshold strip covers the bottom separately) Window Weatherstripping = 2 × (Window Height + Window Width) (full perimeter)
Gap size guide: Standard door gaps:
- Side gaps: 1/16" to 1/8" — use foam tape, V-strip, or door seal
- Top gap: 1/8" — use foam or brush seal
- Bottom gap: up to 3/4" — use door sweep or automatic drop seal
Material quantities: For a standard 36" × 80" door:
- Two sides: 2 × 80" = 160"
- Top: 36"
- Total = 196 inches = 16.3 linear feet (buy 18 ft to allow for overlap and cuts)
Cost estimate formula: Total Cost = Linear Feet × Price per Foot + (Door Sweeps × Price each)
Weatherstripping types:
| Type | Relative cost | Best For | Lifespan |
|---|---|---|---|
| Foam tape | cheapest | Light gaps, windows | 1–3 years |
| V-strip (tension seal) | low | Door sides, sliding windows | 5–10 years |
| Silicone bulb seal | mid | Irregular gaps | 5–7 years |
| Door sweep (brush) | mid | Door bottoms | 3–5 years |
| Door sweep (automatic) | highest | High-end doors | 10+ years |
Prices move enough by region, retailer, and year that any figure printed here would mislead. Enter the price on the roll you are buying and the calculator does the arithmetic. Note the lifespan column though: foam tape is cheapest per foot and needs replacing three or four times over the life of one V-strip, which usually inverts the ranking.
Worked example: Home with 3 exterior doors (36"×80") and 6 windows (36"×48"): Doors: 3 × 16.3 ft = 48.9 ft Windows: 6 × (2 × (3 + 4)) = 6 × 14 = 84 ft Subtotal: 132.9 ft With the 10% waste allowance: 146 linear feet, plus 3 door sweeps
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This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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