Use this workshop calculation to turn measured dimensions and the selected construction convention into a cut, spacing, fit, or material-planning value.

Glass U value (W/(m²K))

Thermal transmittance of the glazing in W/(m²K).

Frame U value (W/(m²K))

Thermal transmittance of the frame in W/(m²K).

Frame share

Frame share of the window area as a fraction between 0 and 0.6.

Compute the window Uw value from the glass U value, frame U value, and frame share. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Window U value (W/(m²K))

Weighted window U value in W/(m²K).

• Nominal dimensions, kerf, moisture movement, hardware clearances, wall squareness, and manufacturer instructions can change the required shop dimension. Measure the actual assembly and test critical joints on scrap before cutting finished material.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Complement the calculated dimension with a physical story stick, dry fit, or full-size layout. Follow the hardware, coating, adhesive, or machine manufacturer's limits where they differ from a rule of thumb.

• Window Glazing Rebate Lookup

  Look up the frame depth and glazing rebate dimensions for Euroframe window profile systems.

• Window Frame List Generator

  Compute the frame piece count, sash count, and glazing bead length for a window frame from its outer size.

• Frame Rabbet Depth

  Size a glazing-frame rabbet from measured glass-and-backing stack thickness plus bedding clearance.