Door Weatherstripping Planner

Calculation and worked example

For each door, the nominal seal length is (2 × height + top width) ÷ 12 feet. Multiply by the door count to get the combined length, then apply the selected allowance to each of the two side cuts and the top cut. The tool places these unbroken pieces into whole rolls using a conservative longest-first approach. Simply dividing the combined footage by the roll size is only a theoretical lower bound; it can suggest too few rolls when leftover pieces cannot be joined. Bottom sweeps are separate items.

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.

Three-door cutting example: seven rolls on paper, eight to buy

For three identical 80-inch-high doors with 36-inch tops, the unadjusted cuts are six 80-inch side pieces and three 36-inch top pieces. Their total is 588 inches, or 49 feet. Dividing 49 feet by an 8-foot roll suggests seven rolls, but that is not a viable unspliced cutting plan:

• Six 8-foot rolls each supply one 80-inch side, leaving 16 inches per roll—too short for a 36-inch top.
• A seventh roll supplies two 36-inch tops (72 inches).
• An eighth roll supplies the remaining 36-inch top.

The cut-aware estimate is therefore 8 rolls, not 7, before an additional allowance. The interactive result updates this distinction for your own measurements. This is a material quantity exercise; it does not verify whether a particular door needs a continuous factory-designed gasket or a different approved seal assembly.

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 jambs and head use three unbroken cuts of 80, 80 and 36 inches, totaling 196 inches (16.33 feet). Two matching doors need 32.67 feet before allowance. Each door's three pieces fit into one 20-foot roll, so two rolls suffice. Shorter rolls may require more purchases than the combined footage alone suggests because offcuts cannot automatically be spliced.

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.