Door Weatherstripping Planner
Measure the top and two sides of each suitable door, select the length printed on your weatherstrip roll, and calculate how many whole rolls to buy. Bottom door sweeps are listed separately to prevent double counting.
Calculation and worked example
For each door, the nominal seal length is (2 × height + top width) ÷ 12 feet. Multiply by the door count, apply an explicitly chosen cutting allowance, then round up to whole rolls based on the actual roll length. Bottom sweeps are counted as separate items rather than added to the top-and-sides length.
Two 80-inch-high, 36-inch-wide doors need (160 + 36) × 2 ÷ 12 = 32.67 feet of perimeter seal. With an illustrative 10% extra, that becomes 35.93 feet. At 20 feet per roll, you would purchase two complete rolls. If both bottoms also need replacement, the list adds two compatible sweeps. Check whether an actual door manufacturer requires a different treatment, approved seal profile or fire/smoke rating.
What this tool does not decide
Before replacing weatherstripping, verify whether the issue is a damaged seal, door alignment, water intrusion or a defective frame. Choose approved compression, kerf or adhesive systems by the actual door construction and installation guidance. An incorrect seal can prevent doors from latching or closing. Do not change a rated fire or smoke door without the approved components and requirements. This is a purchase quantity tool, not an energy-savings estimate.
Read the full door weatherstripping selection and repair guide → and use the separate caulk calculator only for properly specified sealant joints, not for replacing compressible weatherstrip.
Keep frame seals separate from bottom sweeps
For an 80-inch-high, 36-inch-wide door, the two jambs and head use 80 + 80 + 36 = 196 inches, or about 16.33 feet. Two matching doors need about 32.67 feet before an allowance. With 20-foot rolls, round the total upward to two whole rolls.
The bottoms are a separate product decision. Two doors require two suitable sweeps; do not silently add another 72 inches to the same frame-seal roll. Profile, gap range, fixing method and the door's ability to close matter as much as the estimated footage.
Check before the next step
Measure the actual seal path and gap with the door closed. Confirm that the chosen frame seal and sweep suit the door and do not interfere with its latch or required operation.