Window Repair Material Estimator
Estimate the materials needed to repair a window, including replacement glass, glazing compound, weatherstripping, and caulk based on window dimensions and repair type.
Formulas Used
- Glass Area (sq ft) = (Width × Height) ÷ 144 × (1 + Waste%/100)
- Frame Perimeter (ft) = 2 × (Width + Height) ÷ 12 [or user override]
- Glazing Compound (lbs) = Total Pane Perimeter (ft) ÷ 10 ft/lb × Waste Factor [rounded up to 0.1 lb]
- Glazing Points = Total Pane Perimeter (ft) × 2 points/ft × Waste Factor [single-pane only]
- Weatherstripping (ft) = Frame Perimeter (ft) × Waste Factor
- Caulk (tubes) = Frame Perimeter (ft) × Waste Factor ÷ 25 ft/tube [rounded up to 0.1 tube]
Assumptions & References
- Glass area equals the full rough opening (width × height); actual cut size should be ⅛"–¼" smaller per side — confirm with your glazier.
- Glazing compound coverage of 10 linear ft per lb assumes a standard 3/8" × 3/8" triangular bead (DAP 33 / Sarco Dual Glaze product data).
- Caulk coverage of 25 linear ft per 10 oz tube at a 1/4" bead diameter (standard silicone/latex caulk manufacturer data).
- Glazing points: 2 points per linear foot of pane perimeter, spaced ~6" apart (glazing industry standard practice).
- Weatherstripping quantity equals the full frame perimeter; actual product selection (V-strip, foam, rubber) depends on window type and gap size.
- Double-pane and specialty glass units are typically ordered as pre-fabricated insulated glass units (IGUs) and priced per sq ft by the supplier.
- A 10% default waste factor accounts for cutting losses and breakage; increase to 15–20% for complex shapes or first-time DIY repairs.
- References: Glazing Manual (GANA), DAP product data sheets, This Old House window repair guides.